McGRAW-HILL AutomotiveMechanicsSeries BYWILLIAMH.CROUSE AutomotiveEngines AutomotiveFuel,Lubricating,and CoolingSystems AutomotiveChassisandBody AutomotiveTransmissionsandPower Trains AutomotiveElectricalEquipment OTHERBOOKSBYWILLIAMH.CROUSE AutomotiveMechanics andfiveaccompanyingstudyguides: WORKBOOKFORAUTOMOTIVECHASSIS WORKBOOKFORAUTOMOTIVEELECTRICITY WORKBOOKFORAUTOMOTIVEENGINES WORKBOOKFORAUTOMOTIVESERVICE ANDTROUBLESHOOTING WORKBOOKFORAUTOMOTIVETOOLS EverydayAutomobileRepairs AUTOMOTIVE Transmis sions and PowerTrains Construction,Operation,and Maintenance . 1.til jf WilliamH.Cro-asl3' \BOUTTHEAUTHOR BehindWilliamH.Crouse'scleartechnical writing isabackground of sound 'lechanicalengineeringtrainingaswellasavarietyofpracticalindustrialex-,eriences.He spent ayear after finishinghighschool working in atinplate mill, ummers,whilestillinschool,workinginGeneralMotorsplants,andthree 'earsworkingintheDelco-RemyDivisionshops.Later hebecameDirectorof 1ieldEducationintheDelco-RemyDivisionofGeneralMotorsCorporation, I'hichgavehimanopportunitytodevelopandusehisnaturalwritingtalent n the preparation of service bulletinsand educational literature. Duringthewaryears,hewroteanumberoftechnicalmanualsforthe \TmedForces.Mter thewar,he became EditorofTechnicalEducationBooks ortheMcGraw-HillBookCompany.Hehascontributednumerousarticlesto .utomotiveandengineeringmagazinesandhaswrittenseveraloutstanding )Ooks:AutomotiveMechanics,ElectricalApplianceSerVicing,EverydayAu-amobileRepairs,EverydayHouseholdApplianceRepairs,andUnderstanding 'cience. WilliamH.Crouse'soutstandingwork intheautomotivefieldhasearned for limmembershipin theSocietyofAutomotiveEngineersandintheAmerican )ociety forEngineeringEducation. ,UTOMOTIVETRANSMISSIONSANDPOWERTRAINS Copyright 1959 by theMcGraw-HillBookCompany,Inc. Copyright1955by theMcGraw-HillBookCompany,Inc.Printed in theUnited ;tatesofAmerica.Allrightsreserved.Thisbook,orpartsthereof,maynotbere-,roduced inanyformwithout permission of the publishers. of CongressCatalogCardNumber:59-5573 \ \ THEMAl'LB PlIES8COMPANY,You, PA. How to study this book THISISoneofaseriesof fivebooks,calledthe McGraw-Hill Auto-motiveMechanicsSeries,whichcoverindetailtheconstruction, operation,andmaintenanceofautomobiles.The fivebooksarede-togiveyouthecompletebackgroundofinformationyou needtobecomeanautomotivemechanic.Furthermore,everyat-tempt hasbeen made togivesuch thorough coverage of the subject thatthebooksshouldbeavaluableadditiontothelibrary ofany-oneinterestedin_anyphaseofautomobileengineering,manufac-turing,sales,service,and operation. GETTINGPRACTICALEXPERIENCE Ofcourse,thesebooksalonewillnotmakeyouanautomotive mechanic,justasbooksalonedonotmakeanairplanepilotora dentistoranarchitecttheexpertheis.Practicealsoisrequired-practiceinhandlingautomotivepartsandautomotivetoolsandin followingautomotiveservicing procedures.The books willgiveyou thetheoreticalbackgroundyouneed,butyoushouldseekout meansofgetting practice also.If you are taking aregularcourse in automotivemechanics,youwillgetpracticalexperienceinthe schoolautomotiveshop.But ifyouarenottakingaregular course in aschool,you may still be able to make use of the facilitiesof any nearbyschoolwithanautomotiveshop.Perhapsyouwillmeet otherswhoare taking an automotive mechanics cOurseand can talk over problems you have.This often clears up difficult points. A local garageorservicestationisagoodsourceofpractical information. If youcangetacquainted withtheautomotive mechanics there,so muchthebetter.Watchthemastheywork,noticehowtheydo things.Thengohomeandthinkaboutit.Perhapsthemechanics willallowyoutohandlevariouspartsandpossiblyevenhelpwith some of the servicing jobs. [v] HowtoStudyThisBook SERVICEPUBLICATIONS Whileyouareintheserviceshop,trytogetachancetostudy thevariouspublicationsthey receive.Automobilemanufacturersas wellassuppliersof parts,accessories,andtools,publish shop man-uals,servicebulletins,andpartscatalogues.Allofthesearede-signedtohelpservicepersonneldoabetterjob.Inaddition,nu-merousautomotivemagazinesarepublishedwhichdealwiththe problemsandmethodsofautomotiveservice.Allofthesepublica-tions will be of great value to you; study them carefully. These variousactivitieswill help yougain practical experience in automotivemechanics.Soonerorlaterthisexperience,plusthe knowledgethatyouhavegainedinreadingthefivebooksinthe McGraw-HillAutomotiveMechanicsSeries,will permit youtostep into theautomotiveshoponafull-timebasis.Or,if you arealready intheshop,youwillbeequipped tostep up to abetter and amore responsible job. CHECKINGONYOURSELF Everyfewpagesinthebookyouaregiventhechancetocheck theprogressyouaremakingbyansweringaseriesofquestions. Youwillnoticethattherearetwotypesoftests:progressquizzes andchaptercheckups.Eachprogressquizshouldbetakenjust afteryouhavecompletedthepagesprecedingit.Thequizzes allowyoutoquicklycheck yourself asyou finisha"lesson." On the other hand,thechapter checkups may cover several"lessons" since theyare reviewtestsof entirechapters.Sincethey are review tests, youshouldreviewtheentirechapterbyrereadingitoratleast pagingthroughittocheckimportant pointsbeforetryingthetest. If anyofthequestionsstumpsyou,rereadthepagesinthebook thatwillgiveyoutheanswer.Thissortofreviewisveryvaluable andwillhelpyoutofixinyour mindtheessentialinformationyou willneedwhenyougointotheautomotiveshop.Donotwritein the book.Instead, write down your answers in a notebook. KEEPINGANOTEBOOK Mostofthequestionsrequireawritten answer.It will be helpful foryoutokeepanotebookandtowritetheanswersinthenote-book.Also,you can write down in the notebook important facts that youpick up fromreading the book or fromworking in the shop.As [vi] HowtoStudyThisBook youdothis,you will findthatthe notebook willbecome avaluable sourceof informationtowhich you can refer.Usealoose-leaf,ring-bindertypeofnotebooksoyoucaninsertorremovepagesand thereby add to and improve your notebook. GLOSSARYANDINDEX Thereisalistofautomotivetermswiththeirdefinitionsinthe back of the book.Whenever you have any doubt about the meaning of sometermorthepurposeof some automotive part, you can refer tothislist,orglossary.Also,inthebackofthebookyouwillfind anindex.Thisindexwillhelpyouto lookupanything inthebook thatyouarenotsureabout.Forexample,ifyouwanttorefresh yourmindonhowsomecomponentworks,youcanfinditquickly by looking inthe index to findwhat pages the information ison. AUTOMOTIVETOOLSANDCOMPONENTS InAutomotiveEngines(oneofthefivebooksintheMcGraw-HillAutomotiveMechanicsSeries),thereisachapteronauto-motivetools.Thischapterisanimportantoneandshould bestud-iedalongwithanyofthebooksintheMcGraw-HillAutomotive MechanicsSeries.In other words,the information in the chapter on toolsappliestoallserviceoperationsonthecar,notjusttoengine service.Automotive Enginesalso hasachapter on automotivecom-ponentsthatdescribesbrieflytheoperationofallthemechanisms intheautomobile.Referenceshouldbe madeto thischapter if the reader desires ashort explanation of any component. Andnow,goodlucktoyou.Youareengagedinthestudyofa fascinating,complex,andadmirablemechanism-theautomobile. Yourstudiescan leadyoutosuccessintheautomotivefield,afield whereopportunitiesaregreat.Foritisthemanwhoknows-the man who can do things-who moves ahead. Let this man be you. WILLIAMH.CROUSE [vii] P:reface to second edition RAPIDtechnologicaldevelopmentsintheautomotive field,aswell asadvancements in educational methods required to keep pace with thesenewdevelopments,havemadeadvisableaneweditionof Automotive Transmissionsand PowerTrains.Thisrevision includes materialonthenewautomotiveequipmentintroducedinthepast threeyearsandrelatedservicingtechniques.Insofaraspossible, thisnew material hasnotbeenappended totheold;instead,it has been integrated intothepattern ofthetextsothat the student sees the new material aspart of the complete presentation. Thecommentsandsuggestionsofteachersandstudentswho haveusedtheearliereditionhavebeencarefullyanalyzedand acteduponwherepossibleduringtherevisionofthetext.Reports oftheirexperienceintheactualuseofthetextforclassroomand homestudyhavebeenofparamountimportancetotheauthorin hiseffortstomake thebookof maximum usefulness.Improvements thathavebeenmadeinthepresentedition,therefore,shouldbe creditedtotheseusers,andacknowledgmentoftheirhelpfulsug-gestions isherewith gratefully extended. WILLIAMH.CROUSE Conlenls Howtostudythisbook Prefacetosecondedition Acknowledgments 1.POWERTRAINCOMPONENTS 1.Componentsoftheautomobile 2.Power train 3.Clutch 4.Transmission 2.CLUTCHES 9.Functionofclutch 10.Typesof clutches 11.Operationofclutch 3.CLUTCHSERVICE. 14.Clutch trouble-shootingchart 15.Clutchslipswhileengaged 16.Clutchchattersorgrabswhenen-gaging 17.Clutchspinsordragswhendisen-gaged 18.Clutchnoises 19.Clutch-pedalpulsation 20.Rapidfriction-disk-facingwear 21.Clutch pedal stiff 22.Clutch-pedaladjustment 4.TRANSMISSIONS. 31.Functionoftransmission 32.Typesoftransmission 33.Operationoftransmission 34.Four-forward-speedtransmission 35.Constant-meshtransmission 5.OVERDRIVES 39.Purposeofoverdrive 40.Overdrivecomponents 41.Freewheeling mechanism 5.Gearsand torque 6.Operationottransmission 7.Finaldrive 8.Differential 1) viii xiii 1 28 12.Diaphragm-springtypeofclutch 13.Semicentrifugalclutch 44 23.Clutchremovalandreplacement 24.Clutchservice 25.Longclutchservice 26.BorgandBeckclutchservice 27.Auburnclutchservice 28.Diaphragm-springclutch service 29.Crown-pres sure-springclutchserv-ice 30.Inspectingandservicingclutch parts 86 36.Selectorand shifter 37.Vacuumgearshift 38.Vacuum-operatedclutchandgear-shift 120 42.Planetarygearsystem 43.Overdriveoperation 44.Overdriveelectriccontrols 6.STANDARDTRANSMISSIONANDOVERDRIVESERVICE139 45.Diagnosingstandardtransmission46.Transmission and overdrive trouble-and overdrivetroublesshootingchart fix] 47.Hardshiftingintogear 48.Transmissionsticksingear 49.Transmissionslipsoutofgear 50.Nopower throughtransmission 51.Transmissionnoisy 52.Gearsclash inshifting 53.Oilleaks 54.Vacuum-gearshift troubles 55.Overdrive troubles Contents 56.Transmissionremovalandinstalla-tion 57.Transmissiondisassembly 58.Inspection oftransmissionparts 59.Assembly of transmission 60.Steering-columngearshiftmech-anism 61.Overdriveservice 7.TRANSMISSIONSWITHFLUIDCOUPLINGS179 62.Hydraulics68.Hydra-Matictransmission 63.Operationoffluidcoupling69.PlanetarygearsinHydra-Matic 64.Fluidcouplingandclutch70.Planetary-gear-systemcontrol 65.Transmissionusedwithfluidcou- 71.Shiftcontrol pring7:2.Hydra-Matic operation 66.Transmissioncontrols73.Hydraulic controls 67.Vacuum-operatedtransmission 8.TRANSMISSIONSWITHTORQUECONVERTERS.244 9. 74.Fluidcouplingscomparedwith79.Automatictransmissionsusedwith torqueconverters 75.Torqueconverter 76.Torque-converteraction 77.TorqueconverterswithfourIllem-bers 78.TorqueconverterwiththreeIllem-bers GYRO-MATICTYPETRANSMISSION 84.DiagnosingGyro-Matic-transmis-siontroubles 85.Transmissiontrouble-shootingchart 86.Electric-circuit tests 87.Hydraulic-mechanismtests 88.Failuretoupshift 89.Failuretodownshift 90.Car creeps when idling 91.FluidDriveorFluid-TorqueDrive slips 92.Driveisnoisy 93.Fluid-TorqueDriveoverheats torqueconverters 80.Automatictransmissionswithfive-membertorqueconverters 81.Automaticocansmissionswithfour-membertorqueconverters 82.Automatictransmissionswith three-membertorqueconverters 83.Push-buttoncontrols SERVICE317 94.Removingtransmission,clutch, andFluidDrive 95.Removingtransmission,clutch, andFluid-TorqueDrive 96.Servicingtheclutch 97.Servicing theFluid Drive 9S.ServicingtheFluid-TorqueDrive 99.Servicing thetransmission 100.InstallingFluidDrive,clutch,and transmission 101.InstallingFluid-TorqueDrive, clutch,and transmission 102.Towingcartostartengine 10.HYDRA-MATIC-TRANSMISSIONSERVICE.353 103.DiagnosingHydra-Matic-transmis- 106. siontroubles107. 104.TransmissiontestslOS. 105.Factorsaffectingtransmissionop-eration109. I [xl Transmissionremoval Transmission disassembly Disassemblyoftransmission ponents Inspectionofparts com-Contents 110.Reassemblyoftransmissioncom- 112.Installing transmissionincar ponents113.Hydra-Maticadjustments 111.Assemblingcomponentsintocase 11.POWER GLIDEANDTURBOGLIDE 398 114.DiagnosingPowerglideandTur- 132.Installation of Powerglideincar boglidetroubles133.DisassemblyofPower glide(later 115.Transmissiontestsmodel) 116.Oilloss134.Converterdisassembly,inspection, 117.Removaloftransmissionrepairs,andreassembly 118.Disassemblyoftransmission135.Clutch disassembly,inspection,re-119.Primarypumpdisassemblyandpair,andreassembly reassembly136.Modulator 120.Stators-disassemblyandreassem- 1.37.Frontpump biy138.Rearpump 121.Turbineaf"= '" I-:;: ... .sa :rlI- .... '" ...03 is'" I-... '"'" >= => '" 0 J:... I-..=>=l.. Z ON5 z", >'10 0 '! '" SCJ 00 J: A u0... !!!O'" Z ...

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>-I l__ Overdrives43 mainshaft.ThesungearhasanalTangementwherebyitmaybe permittedtoturn or it may be locked in a stationary position.When itislocked,theringgear(andthustheoutputshaft)isforcedto tumfasterthanthetransmissionmainshaft.Inotherwords,the output shaftoverdrivesthetransmissionmainshaft.Variousviews oftheoverdrivepartsshowtheplanetarygear members(Figs.5-9 to 5-15 ). DASH CONTROL (PUSHED(N) FIG.5-10.Overdrive in direct drivewith the transmission main shaft and output shaft turning at samespeed.(AmericanMotorsCorporation) 43.OverdriveoperationFigure5-9showsthecomponentparts ofonetypeofoverdriveinexploded view,withall majorpartsdis-assembledbutlinedupintheirapproximaterelationshipinthe actualassembly.Figures 5-9to5-15show variousoperating aspects oftheoverdriveassembly.Figures5-10and5-11illustratesthe relationshipoftheoverdrivepartsandthepowerpaththrough the overdrive when it isin direct drive.The transmission main shaft [129] 43AutomotiveTransmissionsandPowerTrains and theoutput shaft turn at the same speed,and the drivingaction isthroughtheoverrunningclutchorfreewheelingmechanism.In bothillustrations,thepowerpathisshownbyawhitelineorby arrows.Note that the power path isdirectly tothe clutch cam which issplinedtothetransmissionmainshaft.Fromtheclutchcam,it passesthroughtherollerstotheoutershellorIacewhichisat-tachedtotheoutputshaft.Figure 5-10showstheoverdrive incut-awayviewwhileFig.5-11showstheoverdrivepartlycutaway withtheparts extendedsotheycanbe more easilyseen. FIG.5-11.Overch-iveunitwithcaroperatingindirectdrive,theoverdrive mechanismhavingbeendisengaged.Theassemblyisshowninextendedview withcomponentsseparatedsoallpartscan bemoreeasilyseen.(Studebaker-PackardCorporation) 1.Going into overdrive.In Figs. 5-10 and 5-11,although the over-driveisindirectdrive,it isreadytogointooverdrivejustassoon asthe car speed isgreat enough and the driver momentarily releases theaccelerator.Notethat,inthetwoillustrations,thepawl inthe solenoidisoutofthewayofthesun-gearcontrolplate.It isheld inthispositionbytheblockerringasshownatAinFig.5-12. Theblockerringislooselyassembledontothesun-gearcontrol platesoitcanturnafewdegreesonewayortheother. Whenthecarreachesoverdrivecut-inspeed(roughlybetween 18and21mph), agovernordriven fromthe overdrive output shaft closeselectriccontacts.- Thisconnectsthesolenoidtothebattery andthesolenoidisthereforeenergized.Thisspring-loadsthe solenoid soit attempts to move upward and into a notch in the [130]),_ \ \

Overdrives43 sun-gearcontrolplate.However,thepawlisheldawaybythe blocker ring asshown at A in Fig. 5-12. Whenthedrivermomentarilyreleasestheaccelerator pedal,the enginespeeddrops.Asitdrops,thefreewheelingmechanismgoes intoactiontopermittheoutputshafttooverrunthetransmission shaft.Whenthishappens,theSlillgearslowsandthenreverses directions.Itdoesthisbecausetheringgear(whichrotateswith theoutput shaft )beginstodriveitthroughtheplanet pinions. Atthe momentthatthe sungear reversesdirections, it movesthe blockerring aroundafewdegreesasshown at Bin Fig.5-12.When SUNGUtCONTIOl 'LATEIIOTATING) 'AWL 'fLEASED SUNGf".CONTROL PLATE (STATIONAIYI 'AWL ENGAGED B FIG.5-12.Positionsofthesungearcontrolplate,blockerring,andpawlwith thepawlreleased(A)andwiththepawlengaged(B) .Withthepawlen-gaged,the sun gear isheldstationary. thishappens,thepawl can moveinwardand into the next notch on the sun-gearcontrol plate that comesaround. This locksthe control plate in astationary position. Sincethecontrolplateissplinedtothesungear,thisactionalso locksthesungearinastationaryposition.Now,whenthedriver againstepsontheacceleratorandenginespeedincreases,thecar goesintooverdrive.Withthesungear locked,the power flowisas showninFigs.5-13and5-14.Thetransmissionmainshaftdrives throughtheplanetpinioncage(splinedtothetransmissionmain shaft)andcausesthepinionstorotatearoundthesungearas showninFig.5-7.Theringgearisattachedtotheoutputshaft throughtheouterraceofthefreewheelingmechanism.Thusthe ringgearandoutputshaftoverdrive(turnfasterthan)the trans-LI'1R Collegeof Andhra P ,adesh AgriculturalUniversity ____..... --.3 43AutomotiveTransmissionsandPowe1'Trains PLANETARY CAGE SUNGEAR (HELDSTATIONARY) FIG.5-13.Withthesungearheldstationaryandtheplanet-pilJioncage being drivenbythetransmissionmainshaft,theringgear(andoutputshaft)is forcedtoturnfasterthan(ortooverdrive)themainshaft.(FordDivisionof FordMotorCompany) FIG.5-14.Planetaryoverdriveunitwithcaroperating inoverdrive.Theassem-blyisshowninextendedviewwithcomponentsseparatedsothatallmaybe seeneasily(Studebaker-PackardCorporation) missionmain shaft.Notethat under thiscondition the freewheeling mechanismisfreewheeling.Thatis,theouterraceisoverrunning the clutch cam and thus the transmission main shaft. 2.Comingoutof overdrive.Tocome out ofoverdrive,thedriver merelypushestheaccelerator alltheway down.Thiswouldbethe actionthe \ driverwouldtakewhenhewantsanextraburstof power, example,topassanothercar.Pushing the accelerator all [132] \ Overdrives43 thewaydowncausestheaccelerator pedaltooperateakick-down switch.Operationofthisswitchproducestwoactions.First,it opensthesolenoidcircuitsothatthesolenoidattemptstowith-drawthepawlfromthesun-gearcontrolplate.However,thereis considerablepressureonthepawlsinceitisholdingthesungear stationaryandtheplanet pinionsarethrusting hard against thesun gear asthey drive the ring gear.The second action of the kick-down switchmomentarilyrelievesthisdrive,however,sincethekick-downswitchalsoopenstheignitioncircuitandtherebyprevents theenginefromdelivering power.Sincetheenginewillslow down if itisnot delivering power,thedriving thrust of theplanet pinions onthesungearisalmostinstantly relieved.This freesthesungear andsun-gear control plate andthedrivepawl ispulled back by the springinthesolenoid.Asthedrivepawlplungerinthesolenoid "bottoms,"it reestablishestheelectriccircuit totheignitionsystem sotheengineonceagainbeginstodeliverpower.Now,withthe sungearunlocked,driveisagaindirect asshowninFigs.5-10and 5-11. Theignitionsystemisdisconnectedforsuchashorttimethat theinterruptionoftheflowofpowerisnotnoticeable.Theentire sequenceofeventsthattakesplacewhenthekick-downswitchis closedmaybecompletedinlessthanasecond;thecargoesfrom overdrive into direct drive very quickly. Whenthe driveragainwantstogointooverdrive,he hasmerely tolifthisfootmomentarilyfromtheacceleratorpedalasalready explained. Theelectriccontrolsinvolvedintheoverdriveactionarede-scribedinthefollowingsection.Figure5-16illustratesthewiring circuit ofthe controls. 3.Lockingouttheoverdrive.If thedriverwantstolockoutthe overdrive,hepullsoutacontrolknobonthecardash.Thisforces thecontrolrodinthedirectionshowninFig.5-15.Asthecontrol rodmovesinthisdirection,itforcesthesun-gearcoverplateand sungear to move toward the planet-pinion cage.The sun-gear teeth enterintomeshwithinternalteethintheplanet-pinioncageso that thetwo lock up.Under thiscondition,thesun gear and pinion cagemustturntogether,andthustheentireassemblyturnsasa unitsotherecanbenooverrunningeffect.Themovementofthe controlrodalsooperatesanelectricswitchthatopensthecircuit [133] 44 AutomotiveTransmissionsandPowerTrains betweenthegovernorandsolenoidsothattheelectriccontrol circuit isinoperative. NOTE:Theoverdriveexplainedaboveisbut oneofseveraltypes that havebeenusedonautomobiles.It istypicalofthemall,how-ever,sinceallare essentially similarin constructionand action. FIG.5-15.Positionsoftheinternalpartswhentheoverdriveislockedout. Movementofadashcontrolshiftsacontrolrodwhichlocksupthe sungear andtheplanet-pinioncagesothetwomustturntogether.(AmericanMotors Corporation) 44. Overdriveelectri ccontrolsVarioustypesofelectriccontrols ofoverdriveshavebeenused,butessentially,theyhavethesame purpose.Theymustenergize thesolenoidasthecarreachescut-in speed.Theymustalsodisconnecttheignitioncircuitmomentarily andat the same timeopen the solenoid circuit when the kick-down switchisclosed asthedriverwantstocome out of overdrive. [134]\ /\ \ Overdrives 44 Figure5-16showsawiringcircuitoftheelectriccontrolsystem usedwiththeoverdrivedescribedonpreviouspages.Notethat thesystemalsoincludesanoverdrivelock-outswitch,which isconnectedintothecircuitbetweenthegovernorswitchandthe solenoid.Whentheoverdriveislocked out,thisswitch isopenso thattheelectriccontrolcircuitisinoperative.Letustracethis circuit indetail. Whenthedriverwantstogointooverdrive,hepushesinthe controlknobonthedash.Thisplacesthesysteminthecondition OVERDRIVE SOLENOID BB KICK-DOWN SWITCH RELIIV A TOBATTERV TOIGNITION DISTRIBUTOR OVERDRIVELOCK-OUTSWITCH CONT.CABLEOPERATED OVERDRIVE GOVERNOR DIAGRAMSHOWINGCOMPONENTSOFTHE CIRCUITWITHOVERDRIVELOCK-OUTSWITCH IN"ON" POSITION. FIG.5-16.Electriccircuitof theoverdrivecontrol. shown in Fig.5-10 and connects the governor switch to the solenoid relay(throughtheuppercontactsofthekick-downswitch,asyou willnotice).Whenthecarreachescut-inspeed,thegovernor closesitscontactstoconnecttheoverdriverelaywindingtothe battery.Theoverdriverelay,inturn,closesitscontactstoconnect thesolenoidtothebattery.Now,theoverdriveisreadytogointo action.Whenthedrivermomentarilyreleasesthepedal,thesole-noidcansendthepawlintoanotchinthesun-gearcontrolplate. This puts the transmissioninto overdrive. Tocomeout of overdrive,the driver pushes allthe way downon theacceleratorpedal,thuscausingtheuppercontactsofthekick-[135] 44AutomotiveTransmissionsandPowerTrains downswitchtoopenandthelowercontactstoclose.Openingthe uppercontactsopenstheoverdriverelaycircuit.Theoverdrive relaythereforeopensitscontactstoopenthesolenoidcircuit.Also, closingthe lower contactsinthe kick-downswitch directlygrounds the ignitioncoilandtherebypreventsany ignition.Withthisinter-ruptionofignition-systemaction,the engine stopsdelivering power andbeginstoslow down.Asit doesthis,the thrust of the solenoid pawlisrelieved,andthespringpressurepullsthepawloutofthe notchinthesun-gearcontrolplate.Whenthesolenoidpawlsnaps intothe"out"position,thecontactsinthesolenoidareopenedto "un ground"theignitioncoilandthereby permit the ignitionsystem toagainfunction.Theengineagainbeginstodeliverpower.This seriesofactionstakeplacesoquicklythatnoappreciablelagin power deliveryisnoticeable. CHAPTERCHECKUP NOTE:Sincethefollowingisachapter reviewtest,youshould review the chapter before taking it. Youhavebeenmakingverygoodprogressinyourstudiesofauto-motivepowertrainsandtheircomponents.InChap.4,youstudied varioustransmissionsusedoncars,andinthechapterjust finished,you studiedoverdrives usedwithsomeof thesetransmissions.Actually,there isadoublepurpose inyourstudyingtheoverdrive.First,ofcourse,you shouldknowhowthesedevicesareconstructedandhowtheyoperate. Second,the component partsare used inone wayor another indifferent automatictransmissions.Thus,agoodunderstandingoftheoverdrive willleadtomucheasierunderstandingofthemostintricatetypesof automatictransmissions.Togiveyouachancetocheck yourselfonhow wellyouunderstandandremembertheoverdrive,thefollowingques-tionshave beenincluded.If anyofthequestionscauseyoutrouble,just turnbackintothechapterandrereadthepagesthatwillclearupthe difficulty. CompletingtheSentences Thesentencesbelowareincomplete.Aftereachsentencethereare severalwordsorphrases,onlyoneofwhichwillcorrectlycompletethe sentence.Writeeachsentencedowninyournotebook,selectingthe proper word or phrase to complete it correctly. 1.Theoverdriveislocatedbetweenthetransmissionandclutch transmission and propeller shaftplanetary gears andclutch [136]t\ , Overdrives 2.Thefreewheelingmechanismcontains atransmissionanoverrunningclutch 3.Thenumberofgearsandpinionsinthe describedinthechapteristwo eight aplanetarygear apropeller shaft planetarygearsystem threefive 4.The sun gear in the planetary gear system mesheswith thering gearclutchgearplanetpinionspznzoncage 5.Holdingthesungearstationaryandturningtheplanet-pinioncage causestheringgear toturnslowerthanfasterthan atsamespeed asthe planet-pinioncage. 6.Intheoverdrive,thereisanarrangementwherebyitispossibleto lockstationarytheringgearsungearplanet-pinioncage 1.Inordertogointooverdrive,theplanet-pinioncage sungearringgearmust be prevented fromturning. 8.Whencomingoutofoverdrive,theoverdriveelectriccontrol momentarilydeclutchestheengineinterruptsignition-system actionde-meshes thesungear 9.If theringgearisturnedwhilethesungearisheldstationary,the planet-pinioncagewilltumslowerthanatsamespeed asfasterthanthering gear. 10.If the cageisheldand thesungear isturned,the ringgear will tum inareversedirectionbutslowerthanatsamespeed as fasterthanthesungear. ListingParis In the following,youareaskedtolistpartsthatgointovariousauto-motivetransmissionsdiscussedinthechapter.Writedownthelistsin yournotebook. 1.Make a list of the parts in the planetary gear system. 2.Make a list of the parts in the overrunning clutch. 3.Makealistoftheelectricalcomponentsinthe controlcircuitofthe overdrive. 4.Make a list of major parts in the overdrive. 5.Makealistofthepartsthroughwhichthepowerpasseswhenthe car isin overdrive. Purpose and Operationof Components Inthefollowing,youareaskedtowrite downthepurposeandopera-tionoftheoverdrivesandoverdrivecomponentsdescribedinthe chapter. If you have any difficulty in writing down your explanation,turn [137] AutomotiveTransmissionsandPowerTrains backinthechapterandrereadthepagesthat willgiveyoutheanswer. Then writedown yourexplanation.Don't copy;trytotellit inyour own words,justasyoumightexplainittoafriend.Thisisagoodway tofix theexplanationmorefirmlyinyourmind.Writeinyournotebook. 1.What isthe purpose of the overdrive? 2.Howdoestheplanetarygearsystemworkwhenthesungear isheld stationary? 3.Whatisthepurposeofthesolenoidpawl?Describe theactionsthat permitthepawltoenteranotchinthesun-gearcontrol plate. 4.Explain how the overdrive islocked out. 5.Explainwhat happenswhenthedriver pushestheacceleratorallthe way down tocome out of overdrive. 6.Explaintheoperationoftheelectriccontrolswhenthecarspeed increases to cut-in and the overdrive goes into operation. SUGGESTIONSFORFURTHERSTUDY If you are able toget hold of anoverdriveor the parts of anoverdrive, makeacarefulexaminationofthepartstodeterminehowtheyfitto-getherandoperate.Noteparticularlytheconstructionandoperationof theoverrunningclutchandtheplanetarygearsystem.Studycarmanu-facturers'manualstolearnmoreaboutoverdrives.Whiletheunitde-scribedinthechapter isthemostcommonlyusedoverdrive,other types havebeenused.Learnallyoucanabouttheseothertypesbystudying themanualsorbyactuallyexaminingthem,if possible.Besuretowrite downin yournotebookany important factsyoucomeacross. [138] 6:Standard transmission and overdrive service THIS CHAPTER describes the trouble-shooting,removal,overhaul, andreassemblyproceduresonvariousstandardtransmissionsand overdrives.Followingchaptersdiscusstheoperationandmainte-nanceofthedifferent semiautomatic and automatic transmissions in useonpassenger cars. 45.DiagnosingstandardtransmissionandoverdrivetroublesAsa firststepinanytransmissionoroverdriveservice,diagnosisofthe troubleshouldbemadeinanattempttopin-pointthetroublein themalfunctioningunit.Sometimesitisnotpossibletodetermine theexactlocationofatroubleandtheunit mustberemovedfrom the car soit can be torn down and examined. At other times diagno-siswill lead tothe point of trouble sothat it can be eliminated with-out major disassembly.It isalsotrue that the diagnosis may indicate thatthetransmissionoroverdrivemustbe removed.Nevertheless, itisasavingintimeandeffortinthelong runtoalwayscheckthe operationoftheassemblyonthe carinaneffortto findthe source oftrouble.It maybethatwhatwasthoughttobeacaseoftrans-missiontroubleisactuallyatroublelocatedinsomeothercom-ponent of the car. Thechartthatfollowsliststhevarioustroublesthatmightbe blamedonthetransmissionoroverdrive,togetherwiththeirpos-siblecauses,thecheckstobe made,and thecorrectionsneeded. 46.Transmissionandoverdrivetrouble-shootingchartThechart belowisdividedintothreeparts:TransmissionTroubles,Vacuum-gearshiftTroubles,andOverdriveTroubles.Mosttransmission troublescan be listed under afewheadings such as"hard shifting," "willnotstayingear,""noises,"andsoon.Inthechart,possible causesofthe varioustroublesare listed,and referencesare made to [139] 46AutomotiveTransmissionsandPowerTrains numberedsectionswherefullerexplanationsarefoundofhow to find and eliminate the troubles. NOTE:Thetroublesand possiblecauses are not listed in the chart intheorder of frequencyof occurrence.That is,item1(or item a) doesnot necessarilyoccur morefrequentlythat item 2(or itemb). TRANSMISSIONTROUBLE-SHOOTINGCHART (See47to53fordetailed explanationsof troublecausesand correc-tionslisted below.) Complaint 1.Hard shifting into gear(47) 2.Transm iss ion sticksingear ( 48) 3.Transmission slips outoffirstorre-verse(49) [140] \ \ \ TransmissionTroubles PossibleCause aClutchnotreleas-ing b.Gearshiftlinkage outofadjustment c.Improperlubrica-tionoflinkage d.Shifter forkbent e.Slidinggeartight onshaft splines f.Sliding-gearteeth battered g.Synchronizingunit damaged a.Clutchnotreleas-ing h.Gearshiftlinkage outofadjustment c.Improperlubrica-tionoflinkage d.Detent balls(lock-out)stuck e.Gearstighton shaftsplines a.Gearshiftlinkage outofadjustment b.Gear loose on main shaft c.Gearteethworn d.Excessive endplay ofgears CheckorCorrection Adjust.See17 Adjust Lubricate Replaceorstraighten Cleansplinesorre-placeshaftorgear Replace Replacedefective parts Adjust.See17 Adjust Lubricate Free Cleansplinesorre-place shaft or gears Adjust Replaceshaftorgear Replacegear Replace worn or loose parts StandardTransmissionandOverdriveService Complaint 4.Transmission slips outofsecond ( 49) 5.Transmission slips out of high(49) 6.No power through transmission (50) 7.Transmission noisyinneutral (51) PossibleCause e.Insufficientshift-leverspring(lock-out)tension f.Bearingsworn a.Gearshiftlinkage outofadjustment h.Gear or drum loose onmainshaft c.Excessive main-shaft end play d.Gearteethworn e.'Insufficientshift-leverspring(lock-out)tension a.Gearshiftlinkage outofadjustment h.Misalignmentbe-tweenengineand transmission c.Excessive main-shaft end play d.Gearteethworn e.Insufficientshift-leverspring(lock-out)tension f.Bearingsworn g.Synchronizing unit wornordefective a.Clutchslipping h.G eartee th stripped c.Shifterforkor otherlinkagepart broken d.Gearorshaft broken e.Drivekeysheared a.Transmissionmis-alignedwithen-gine h.Bearingswornor dry 46 CheckorCorrection Installnewspring Replace Adjust Replacewornparts Replacewornorde-fectiveparts Replacegears Installnewspring Adjust Realign Replacewornorde-fectiveparts Replacegears Replacespring Replace Replacewornparts Adjust(15) Replacegear Replace Replace Replace Realign Replace,lubricate [141] i / 46 Complaint 8.Transmission noisyingear (51) 9.Gearsclashin shifting(52) 10.Oilleaks(53) [142] AutomotiveTransmissionsandPowerTrains PossibleCause c.Gearsworn d.Countershaft Worn or bent e.Excessive end play ofcountershaft a.Clutchfriction diskdefective b.Enginetorsional-vibrationdamp-enerdefective c.Mainrearbeating oftransmission wornor dry d.Gearslooseon mainshaft e.Gearteeth worn f.Speedometer gears worn g.Conditionsnoted initem7,Trans-missionnoisyin neutral.Referto item7,above,for othercauses. a.Clutchnotreleas-ing b.Synchronizerde-fective c.Gearsstickyon mainshaft a.Improperlubri-cant b.Lubricant level too high c.Gasketsbrokenor missing d.Oilsealsdamaged or missing e.OilsHngersdam-aged,improperly installed,ormiss-ing CheckorCorrection Replace Replace Replacewornparts Replace Replaceoradjust Replaceorlubricate Replacewornparts Replacegears Replace Adjust Replacedefective parts Free.Replacedefec-tive parts Userecommended lubricant Useproperamount, nomore Install newgaskets Install new oilseals Installoilslingers properly StandardTransmissionandOverdriveService ComplaintPossibleCause f.Drain plug loose g.Transmissionbear-ing-retainerbolts loose h.Transmissioncase cracked Vacuum-gearshiftTroubles 46 CheckorCorrection Tighten Tighten Use newcase (The vacuumgearshift may have any of the troubles listedin thechart above.Inaddition,therearecertainspecialtroublesitmayhave,as follows. ) 11.Hardshifting (54) 12.Shiftleverjams ( 54) 13.Slippingoutof mesh(54) 14.Gearp0sit ion b I 0eke dout ( 54) Vacuumcylinderin-operative a.Pivot pinsbinding b.Bent rodor lever c.Linkageout ofad-justment a.Defectivevacuum cylinder b.Linkages out of ad-justment a.Bentlinkagerod b.Linkageout of ad-justment c.Mechanicalinter-Eliminatevacuum line leaks, adjust linkages,replace damagedpistonor valvesin cylinder Free,adjust Straighten,replace Adjust Replacevalves,pis-ton,orother defec-tivepart Adjust Straighten Adjust Eliminateinterfer-ferencearoundence vacuumcylinder OverdriveTroubles (The overdrive may have any of the trouble listed below. Be careful, in analyzingtroubleonacarequippedwithoverdrive,nottoblame theoverdrivefortroublesinthetransmission,orviceversa.For example,acertainoverdrivetroublemaypreventshiftingthetrans-missionintoreverse.It wouldbeeasytoblamethisonthe transmission, whereas the fault would actually lie in the overdrive.) [143] 46 Complaint 15.Willnotgointo overdrive( 55, 1) 16.Willnotcome outofoverdrive (55,2) 17.Cannotshiftinto reverseandover-drivedashknob jammedinOD position(55,3) \ \\ \ [1411\, AutomotiveTransmissionsandPowerTrains PossibleCause a.Wiringdefective b.Governor defective c.Kick-downswitch defective d.Relaydefective e.Solenoiddefective f.Linkagetocontrol knobondashout ofadjustment g.Defectinover-driveincluding gearjammedor broken,overrun-ningclutchdefec-tive,excessiveshaft endplay a.Wiringdefective h.Kick-downswitch defective c.Solenoiddefective d.Pawljammed e.Sungearjammed a.Pawljammedin sun-gearcontrol plate h.Solenoiddefective c.Relaydefective d.Governor grounded e.Reverselock-out switchgrounded f.Kick-downswitch defective g.Wiringdefective h.Sungearjammed CheckorCorrection Tightenconnections, installnewwiring Installnewgovernor Installnewswitch Installnewrelay Installnewsolenoid Adjust Disassemble0v e r -drivetoeliminate defectivepar t , tightenflangenut Tightenconnections, installnewwiring Installnewswitch Installnewsolenoid Freepawl Disassemble0ve r -drivetoeliminate jamandreplace defectiveparts Replacesolenoid Replacesolenoid Replacerelay Replacegovernor Replaceswitch Replaceswitch Tightenconnections, replacewiring Disassemble0ve r-drivetoeliminate jam StarulardTransmissionandOverdriveService ComplaintPossibleCause 18.Nopowerthrough overdrive( 55, 4) 19.Noisesinover-drive(55,5) i 20.Oil leaks(55, 6) i.Linkagetodash knoboutofad-justment a.0verr u n n i ng clutchslipping b.Planetarypar t s broken a.G ear sworn, chipped,broken b.Main-shaftbear-ing worn or scored c.0verr u n n i n g clutchpartsworn orscored a.De fee ti v eor brokengasketsor oilseals h.Loosemounting c.Excessive lubricant

CheckorCorrection Adjust Replacedefective partsinoverdrive Replacedefective parts Replacedefective gears Replace Replace Replace Tightenmounting bolts Putinonlyspecified amount,nomore 47.HardshiftingintogearHardshiftingintogearmightbe caused by improper linkageadjustmentbetweenthegearshiftlever andthetransmission.Improperadjustmentmightgreatlyincrease thepressurenecessaryforgearshifting.Thesametroublecould resultwhenthelinkageisbadlyinneedoflubricationandis rustedor jammed at any of the pivot points.Adjustment and lubri-cation of linkages isdiscussed in 60. Another cause ofthistroublecould be due to failureof the clutch to releasecompletely.If the clutch linkage isout of adjustment or if otherconditions,asoutlinedin17,preventfullclutchdisengage-ment,then it willbe difficultto shift gears into or out of mesh.Gear clashing willprobably resultsincethe engine will still be delivering atleastsomepowerthroughtheclutchtothetransmission.See 17 forcorrections of this sort of clutch trouble. Insidethetransmission,hardgearshiftingcouldbe causedby a bentshifterfork,slidinggeartightontheshaftsplines,sliding-gear teeth battered, or adamaged synchronizing unit.A bent shifter fork,whichmightmakeitnecessarytoexertgreaterpressurein ordertoshiftgears,shouldbereplacedor,ifnottoobadlybent, [145] 48AutomotiveTransmissionsandPowerTrains straightened.Thesplinesinthegearsorontheshaft maybecome gummeduporbatteredfromexcessivewearsothatthegearwill notmoveeasilyalongtheshaftsplines.If thishappens,theshaft andgearsshould becleanedor,ifworn,replaced.If thegearteeth arebattered,theywillnotslipintomesheasily.Nothingcanbe done to repair gears with battered teeth; new gears will be required. Thesynchronizing unit couldbe tighton the shaft,or it could have loosepartsorwornorscoredcones;anyofthesewouldincrease thedifficultyofmeshing.Toclearuptroublesinthetransmission, itmustberemovedanddisassembled.Sectionsinthe latter part of the chapter describe these operations. 48. TransmissionsticksingearAnumberoftheconditionsthat causehardshiftingintogearcanalsocausethetransmissionto stickingear.Forinstance,improperlinkageadjustmentbetween thegearshiftleverandthetransmission,aswellaslackoflubrica-tioninthe linkage,could makeit hardtoshiftout of mesh.Adjust-ment and lubrication of linkages isdiscussed in 60. Another cause could be failureof the clutch to release completely. Improper clutch-linkage adjustment, aswell asother conditions out-linedin17thatpreventfullreleaseoftheclutch,couldmakeit hardtoshiftoutofmesh.See17forcorrectionofthistypeof clutchtrouble. If thedetentballs(orthelock-outmechanisminthetransmis-sion)stickanddonot unlockreadilywhenshifting isattempted,it willbehardtoshiftoutofgear.Theyshouldbefreedand lubricated. If thegearsdonotslidefreelyontheshaftsplines,thenitwill be hard to come out of mesh.The shaft and gears should be cleaned or,ifworn,replaced.Seethelatterpartofthischapterfortrans-missionremoval,disassembly,reassembly,andreplacementpro-cedures. 49. TransmissionslipsoutofgearImproperlyadjustedgearshift linkagebetweenthegearshiftleverandtransmissionmightpro-ducepressureonthelinkageinsuchawaythatgearswould work out of mesh.Linkage adjustment isoutlined in60. Worngearsorgearteethmayalsoincreasethechancesofgears comingoutofmesh.Likewise,ifthedetentballs(orlock-out mechanisminthetransmission)lacksufficientspringpressure, [146] StandardTransmissionandOverdriveService51 therewill be littleto hold thegearsin mesh and they may slipout. Wornbearingsorgearslooseontheshafttendtocauseexcessive end play or free motion that allows the gears to de-mesh. Inaddition,ifthe transmissionslipsout of high gear,it couldbe duetomisalignmentbetweenthetransmissionandtheengine. ThisisaseriousconditionwhichcanSOondamagetheclutchas wellastransmissionparts.Thismisalignmentcan often be detected bytheactionoftheclutch pedal;itcausesclutch-pedal pulsations oranervouspedalasexplainedin19.Section30describesthe procedureofcheckingclutchhousingalignment;iftheclutch housingisout of line,thenthetransmissionwill alsobe out of line. 50.NopowerthroughtransmissionIf thetransmissionisin mesh andtheclutchisengagedandyetnopowerpassesthroughthe transmission,thenit could bethattheclutchisslipping.Section15 describesvariouscausesofclutchslippage.Iftheclutchisnot slipping,thenthetroubleisinthetransmissionandtheindication isthatsomethingserioushastakenplacewhichwillrequirecom-pletetransmissionoverhaul.Conditionsinsidethetransmissionthat wouldpreventpowerfrompassingthroughincludegearteeth strippedfromgear,shifterforkor other linkagepart broken,agear orshaftbroken,andadrivingkeyorsplineshearedoff.Thetrans-missionmustbetakenoffanddisassembledasexplainedinthe latterpartofthechaptersothedamagedorbrokenpartscanbe replaced. 51. TransmissionnoisySeveraltypesof noisemay beencountered in transmissions.Whining orgrowling, either steady or intermittent, maybeduetoworn,chipped,rough,orcrackedgears.Asthe gearscontinuetowear,thenoisemay take on agrinding character-istic,particularlyinthegearpositionthatthrowsthegreatest load ontheworngears.Bearingtroubleoftenproducesahissingnoise thatwilldevelopintoabumpingorthuddingsoundasbearings wearbadly.Metallicrattlescouldbeduetowornorlooseshifting partsinthe linkageor togears looseonshaft splines.Sometimes,if theclutchfriction-diskcushionsprings,ortheenginetorsional-vibrationdampener,aredefective,thetorsionalvibrationofthe enginewillcarrybackintothetransmission.Thiswouldbeap-parent only at certain engine speeds. [147] 52AutomotiveTransmissionsandPowerTrains Asafirststep in analyzing noise inthe transmission, note whether thenoiseisobtainedinneutral withthecarnotmovingorincer-taingearpositions.If thenoiseisevidentwiththetransmissionin neutralwiththecarnotmoving,disengagetheclutch.If thisdoes notstopthenoise,thenthechancesarethetroubleisnotinthe transmissionatall(providedtheclutchactuallydisengagesand doesnothavetroublessuchasoutlinedin17).Inthiscase,the noiseisprobablyintheengineorclutch.Butifthenoisestops whentheclutchisdisengaged,thenthetroubleisprobablyinthe transmission. Noiseobtainedinneutralwiththeclutchengagedcouldcome fromtransmissionmisalignmentwiththeengine,wornordry bear-ings,worngears,aworn or bent countershaft,or excessiveend play ofthecountershaftNoticethatthesearethepartswhicharein motionwhentheclutchisengagedandthetransmissionisin neutral. Noiseobtainedingearcouldresultfromanyoftheconditions notedinthepreviousparagraph.Also,itcouldbeduetoadefec-tivefrictiondiskintheclutchoradefectiveenginetorsional-vibrationdampener.In addition,the rear main bearing of the trans-mission could be wornor dry,gears could be loose on the main shaft, or gearteethcouldbe worn.Anothercauseofnoisecouldbe worn speedometergears.Carefullisteningtonoticetheparticulargear positioninwhichthemostnoiseisobtainedisoftenhelpfulin pin-pointing the worn parts producing the noise. Worntransmissionpartsshouldbereplacedaftertransmission removalanddisassembly,asoutlinedinthelatterpartofthe chapter. 52. GearsclashinshiftingGearclashingthataccompaniesshift-ingintoeithersecondorhighmaybeduetofailureofthesyn-chronizingmechanismtooperateproperly.Thismightbecaused byabrokensynchronizerspring,incorrectsynchronizerendplay, ordefectivesynchronizerconesurfaces.Itcouldalsobedueto gears sticking onthe mainshaft or to failureof the clutch to release fully.Gearclashcanbeobtained inloworreverseonmanycarsif asuddenshiftismadetoeitherofthesegearswhilegearsarestill inmotion.ThesetwogearpOSitionsordinarilydonothavesyn-chrome$ \ devices,andtopreventgearclashwhenshiftinginto [148]\ !\ \ '\ \ StandardTransmissionand OverdriveService55 eitherofthesepositions,itisnecessarytopauselongenoughto allowthegearstocometorest.Ofcourse,iftheclutchisnot releasingfully,thenthegearswillstillbedrivenandmayclash whenthe shift ismade. Conditionsthatmaypreventtheclutchfromreleasingfullyare discussedin17.Thelatterpartofthischapterdescribestrans-missionremovalanddisassemblytoreplacedefectivesynchromesh parts. 53.OilleaksIf thelubricantinthetransmissioncaseisnotof thecorrecttype,itmayfoamexcessively.Asit foams,it willcom-pletelyfillthecaseandbegintoleakout.Thesamethingmight happenifthe oil level istoo high.In addition,ifgasketsare broken ormissingorifoilsealsoroilslingersaredamagedormissing,oil willworkpasttheshaftsatthetwoendsofthetransmission.Also, ifthedrainplugislooseorifthetransmissionbearingretaineris nottightlyboltedtothecase,thenoilwillbelost.Acrackedcase willalsoleakoil.The rightamountoftherecommendedoilshould beusedinthetransmissiontopreventexcessiveoilleakagefrom foaming.Thelatterpartofthechapterexplainshowtoremove anddisassemblethetransmissionsothatdefectivegaskets,oil seals,and slingerscan be replaced. 54.Vacuum-gearshifttroublesInadditiontothetransmission troublesdescribedabove,thevacuum-gearshifttransmissionmay besubjectattimestootherdifficultiesresultingfromimproper actionofthevacuum-gearshiftmechanism.Whenshiftingishard, itislikelythatthevacuumcylinderisnotoperatingnormally becauseofvacuum-lineleaks,adamagedpistonorvalves,orim-properlyadjustedlinkages.Failureoftheshiftlevertoreturnto thebottompositionwhenreleasedisduetobindingatthepivot pins,antirattlebushings,orlinkage,ortoabentrodorlever.If thetransmissionslipsoutofgear,itmaybeduetoadefective vacuumcylinderOrimproperlyadjustedlinkage.Blockingoutofa gearpositionwillresultfromabent rod,improperlyadjustedcon-trolleverorlinkages,ormechanicalinterferenceinoraroundthe vacuumcylinder. 55.OverdrivetroublesCertainconditionsintheoverdrivewill causesuchtroublesasfailuretogointooverdrive,failuretocome [149] 55AutomotiveTransmissionsandPowerTrains outofoverdrive,inabilitytoshiftintoreverseortopullthedash controlknoboutfromtheoverdriveposition,powernotpassing throughtheoverdrive,noises,andoilleaks.Trouble-shootingthese various conditions isdetailed in following paragraphs. 1.Willnot gointooverdrive.If thetransmissionwillnotgointo overdrive,thenaseriesofelectricaltestsmustbemadetodeter-minewhetherthevariouselectrical componentsareinnormalcon-")6BLACK "13 _TO RELAY SHIFTRAIL "LOCK-OUT"SWITCH FIG.6-1.Completeelectriccircuitforanoverdrive.Thenumbersindicateter-minalsandwirestobecheckedandareidentifiedinthetext.(Studebaker-PackardCorporation) dition.RefertoFig.6-1todeterminepointsintheelectriccircuit tomakethefollowingchecks.First,checkthefuseintheover-driverelay.If itisO.K.,removethewirefromthegovernor(No. 15),turnonignitionswitch,andtouchthewirecliptoground.If aclickisheard,thechancesarethegovernorisdefectiveandit shouldbereplaced. If noclickisheard,usea6-voltlampinasockettowhichtwo wiresareco,nnected(Fig.6-2)tocheck forcurrent in variousparts ofthecircuitasexplainedbelow.Putonewireendonterminal [150] StandardTransmissionandOverdriveService55 No.2oftherelayandtheotherwireonground.If the lampdoes not light(ignitionswitchon),replacethe relay.If the lamp lights, checkfurtherwiththetestlampatterminalNo.9onthekick-downswitch.If thelampdoesnotlight,replacetheswitch.If it does,thencheckforcurrentatterminalNo.14ofthelock-out switch.If thelampdoesnotlight,replacetheswitch.If itdoes, thencurrent isavailablethroughthe circuit sofarchecked. Next,usethetest lamp to check forcurrent at terminal No.15 on thegovernor(lead reconnected tothisterminal).If the lamp again lights,thecircuitfromtheignitionswitchtothegovernorisin normalcondition,andthecircuittothesolenoidmustbechecked. FIG.6-2.A split lamp,consistingof asocketwithtwotestwiresandaSocket ", lamp.Thisdevicecanbeusedto locateopenorcompletedcircuits sincethelampwilllightwhenthe testwiresareconnectedacross voltage. ThisisdonebyfirstgroundingrelayterminalNo.2withalead copnectedfromthisterminaltoground.Thencheckforcurrent with the test lampat terminalNo.4. If the lampdoesnot light,the relayshouldbe replaced.If it doeslight,thengroundterminalNo. 15onthegovernor and checkwithtestlamp fromterminalNo.11 onthesolenoidtoground.If thelamplights,thenthesolenoidis defective and it must be replaced. Inadditiontotheelectricaltests,certainconditionsinthe over-drivewillpreventitfromgoingintotheoverdriveposition.If the electricalchecksprovethe electric systemisnormal,thenthe over-drivemustberemovedanddisassembledtodeterminewhathas causedthedifficulty.Oneconditionthatdoesnotrequireremoval anddisassemblyisalooseuniversal-jointcompanion-flangenut. Thisallowsshaftendplaywhichmightpreventoverdriveaction. The nut canbetightened by detaching the universal fromthe com-panionflange. [151] SS AutomotiveTransmissionsandPowerTrains 2.Willnotcomeoutof overdrive.RefertoFig.6-1andusea6-volttestlampasshowninFig.6-2totestcomponentsforcurrent asfollows:Withignitionswitchturnedonanddistributorcontact pointsopen, push kick-downswitch into "down" position and check forcurrentatterminalNo.12onthesolenoid.If thereiscurrent, thesolenoidshouldbereplaced.(Also,mechanicaltroubleinthe overdrivewhichhasjammedthesolenoidpawlorsungearcould beholdingthemechanisminoverdrive.)If thereisnocurrentat terminalNo.12,checkforcurrentatterminalNo.8ofthekick-downswitch.If thereiscurrent,adjusttheswitch linkageinanat-tempttogetcurrentthroughtoterminalNo.12whenthekick-downswitchispusheddown.If adjustmentdoesnothelp,replace theswitch. 3.Willnot shift intoreverseand overdrive dashknobisjammed inODposition.RefertoFig.6-1inmakingtheelectrical teststhat follow.First,turnignitionswitchonandoff.If aclickisheard inthesolenoidwhentheswitchisturnedoff,onesetoftestsisto be made.If noclickisheard,asecondset of testsistobe made. a.If aclickisheardinthesolenoid,if thetransmissioncannow be shifted into reverse,and if the knob can now be pulled out, thendisconnectleadfromterminalNo.15onthegovernor with theignitionswitchon.If aclickcanagainbeheard,the governorisgroundedanditshouldbereplaced.If noclick isheard, reconnect lead toterminal No.15and disconnect lead fromterminalNo.13of thelock-outswitch.If aclick isheard, theswitchisgroundedanditshouldbereplaced.If noclick isheard,reconnectleadtoterminalNo.13anddisconnect leadfromterminalNo.7ofkick-downswitch.If aclickis heard,theswitchisgroundedandshouldbereplaced.If no clickisheard,reconnect lead to terminal No.7and disconnect leadfromterminalNo.4ofrelay.If aclickisheard,replace relay.If no click isheard,then proceed asexplained in follow-ing paragraph. b.If noclickisheardwhenmakingtheoriginaltest by turning theignitionswitchonandoff,asexplainedinparagraph beforelast,theprobabilityisthattheoverdrivesolenoidisat fault.Itshouldbereplaced.Ifthesolenoidcanbepulled straightoutwithoutturningonewayortheother,checkthe [152] " \ 1\ \ \ '\ \ \ StandardTransmissionandOverdriveService55 pawlcontrolrodtoseeifitiswornordefective.If therod willnot turn,try topull pawl out.If it will not come,pawl can usually be released by working it loose with a smallrod pushed throughthesolenoidholeintheadapterplate.If itwillnot comefree,theoverdrivemustbedisassembled. 4.Nopower throughoverdrive.Thisconditioncouldresultfrom brokenplanetarypartsorwornorbrokenoverrunning-clutchcom-ponentswhichpermittheclutchtoslipinthedrivingposition. Eitheroftheseconditionsrequiresdisassemblyoftheoverdrive sodefective parts can be replaced. 5.Noisesintheoverdrive.Noisesinthe overdrive can arisefrom conditionssimilartothoseinthe transmissionwhich produce noise. Thus,wornorchippedgears,wornbearings,orwornoverrunning-clutchpartswillcausenoise.Damagedpartsmustbereplaced after the unit isdisassembled. 6.Oilleaks.Oilwillleak fromtheoverdriveif thereisexcessive lubricant,ifthemountingisloose,oriftherearedefectivegaskets oroilseals.Defectivegasketsoroilsealsmust,ofcourse,be replaced. CHECKYOURPROGRESS ProgressQuiz7 .Knowledgeofwhattocheckforandwhattoexpectwhencertain troublesoccur helpsgreatly indiagnosingtroubles. If you are acquainted withthevariouspossibleconditionsthatcouldcauseacertaintrouble, youwillfinditmucheasiertolocatethecausequickly.Thus,thema-terialjustcoveredwillproveofgreatvaluetoyouasyougointothe serviceshopandbegintoservicecarswith varioustypesoftransmission trouble.Thequizbelowwillhelpyoufindoutjusthowwellyouare rememberingthematerial.It willalsohelpyoutoreviewthematerial sothattheimportantpointswillbefixedmorefirmlyinyourmind.If anyofthequestionsstumpsyou,rereadthepagesthat givetheanswer. CorrectingTroublesLists Thepurposeofthisexerciseistohelpyoutospotrelatedandunre-latedtroublesonalist.Forexample,inthe list,hardshiftingintogear: clutchnotreleasing,linkageoutofad;ustment,differentialdefective, shifterforkbent.slidinggeartightonshaft.gearteethbattered,you [153} 56AutomotiveTransmissionsandPowerTrains canseethatdifferentialdefectivedoesnotbelongbecause it istheonly conditionthatwouldnotcausehardshiftingintogear.Anyoftheother conditions in the list could cause thistrouble. In eachofthe lists,youwillfindone itemthat doesnotbelong.Write downeachlistinyournotebook,butdonotwritedowntheitemthat doesnot belong. 1.Hardshiftingintogear:clutchnotreleasing,linkageoutofadjust-ment,shifterforkbent,sliding-gearteethbattered,geartighton shaft,crankshaft worn,synchronizing unit damaged. 2.Transmissionsticksingear:clutchnotreleasing,linkageoutof adjustment,transmissionshifter-lock-outstuck,distributorjammed, gearstight on shaft splines. 3.Transmissionslipsout of firstor reverse:clutch notreleasing,linkage outofadjustment,gearlooseonshaft,gearteethworn,excessive end play of gears,bearings worn. 4.Transmissionslipsoutofsecond:linkageoutofadjustment,idler gear loose,gear teeth worn,excessive end play of main shaft. 5.Transmissionslipsoutofhigh:clutchslipping,transmissionmis-aligned,gearsorbearingsworn,excessivemain-shaftend play. 6.Nopowerthroughtransmission:clutchslipping,gearteethstripped, shifter-linkagepartbroken,gearorshaftbroken,propellershaft bent. 7.Transmissionnoisyinneutral:transmissionmisalignedwithengine, synchromeshconesworn,bearingsorgearsworn,countershaftbent or hasexcessive end play. 8.Transmissionnoisyingear:bearingsorgearsworn,clutchfriction diskdefective,enginetorsonial-vibrationdampenerdefectiveand allowingenginevibrationtoappearintransmission,gearslooseon mainshaft,steeringgear worn. 9.Gearsclashinshifting:clutchnotreleasing,synchronizerdefective, gearsstickyonmainshaft,overrunningclutchslipping. 10.Oilleaksfromtransmission:foaming,excessivelubricant,gaskets defective,oil sealsdamaged, clutch slipping. 56. TransmissionremovalandinstallationBecause of the variations inconstructionoftransmissionsondifferenttypesofautomobile, differentproceduresmustbefollowedintheremoval,disassembly, repair,assembly,andinstallationoftheirtransmissions.These operationsrequirefromabout5to7hours,thedifferenceintime beingdueto.variationsintheprocedures.Basically,however,the procedures similar,althoughitmaybefoundhelpfultorefer [154]\ 1\ StandardTransmissionandOverdriveService56 tothemanufacturer'sshopmanualbeforeattemptingsuchwork. In general, the following steps are required: 1.Drainlubricant.Somemanufacturersrecommendflushingthe transmissionbeforeremoval.Thisisdonebyfillingthetrans-mission with gasoline or kerosene after the lubricant isdrained, and thenoperating theengine with the transmissionin neutral for15 seconds. Then the cleaner should be drained. 2.Disconnectrearaxle,frontendofpropellershaft,or universal joint,accordingtotype.Whereneedlebearingsareused,tape thebearingretainerstotheshafttoavoidlosing needles. ,FIG.6-3.Installing enginesupport priortoremoval oftransmission. 3.Disconnectshiftinglinkagesfromtransmission,hand-brake linkage or spring,and speedometer cable. 4.Install engine support,where specified(see Fig.6-3). 5.Removeattachingboltsorstudnuts.Whererecommended, twopilotorguidepinsshouldbeused(Fig.6-4).Thesepins aresubstitutedfortransmissionboltsandpreventdamageto theclutchfrictiondiskasthetransmissionismovedback. Thetransmissionisthenmovedtowardtherearuntilthe maingearshaftclearstheclutchdisk.It canthenbe lowered tothefloororraisedupthroughthebody,asspecified. 6.Ingeneral,installationisthereverseofremoval.Besurethe matchingfacesofthetransmissionandflywheelhousingare clean.Placeasmallamountoflubricanton thesplinesofthe [155] 57AutomotiveTransmissionsandPowerTrains maingearshift.Carefullysupporttransmission(usingguide pinsifspecified)andmoveitforwardintoposition.Turn shaft,if necessary,tosecure alignment of shaft and clutch-disk hubsplines.Put boltsinplaceandtightenthemtothe correct tension. Caution:If thetransmissiondoesnotfitsnuglyagainstthefly-wheelhousing,donotforceit.Roughnessordirt,orpossiblya FIG.6-4.Useofguide,orpilot,pinsintransmissionremovalorreplacement. Thepinsmaintaintransmissionalignmentwiththeclutchasthetransmission ismoved back orforwardsothat the clutch will not be damaged.(BuickMotor Divisionof GeneralMotorsCorporation) loosesnapringorotherpart,may beblockingthetransmission.If theboltsaretightenedundersuchcircumstances,thetransmission case may be broken. 57.TransmissiondisassemblyTransmissionservicerequiresa number ofspecial tools,and transmissiondisassembly should not be attempted\ withoutthem.Followingpagesdescribeandillustrate thesetoolsiT}use.Becausetransmissionconstructionvarieswith [1561 \. StandardTransmissionandOverdriveService57 differentcars,it issuggestedthatthemanufacturer'sshopmanual be referred tobefore disassembly isattempted.Typical disassembly procedures follow. 1.Chevrolet.Afterthetransmissionhasbeen removedfromthe car,itmaybemountedinaspecialholdingfixturetofacilitateits disassembly(Fig.6-5).Thenproceedasfollows:Removefour screws,shiftercover,theshifterassembly.Placethe transmissionin twogearsatoncetolockthemainshaft.Inshiftinggearsinto secondorthird,usecaretoavoiddamagingparts.Detachthe FIG.6-5.Use ofatransmission-holding fixture.The transmissionisbolted tothe fixtureandthefixtureisclampedintoavise.(ChevroletMotorDivisionof GeneralMotorsCorpo'ration) universal-jointfrontyokeandspacerbyremovingthescrewand the lock washer. Removeclutchgearandbearingbyremovingfourbearing-re-tainerscrewsandlockwashersandtheretainer.A specialpulleris requiredtoremovethegear andthe bearing(Fig.6-6).Do not at-tempttodrivethegear andthe bearingout,sincethiswill damage thebearingandbearingsurfaces.Removethe14rollerbearings from inside the clutch gear. Tumtheyokeofthespecialmain-shaftremovingtoolbackon thethreadsand screwthe pullershaft into the threaded end ofthe mainshaft.Boltthe yokeofthe tooltotIlefaceof thetransmission case(Fig.6-7).Turnthefrontsynchronizerringtolineupthe [157} 57 AutomotiveTransmissionsandPowerTrains FIG.6-6.Specialclutch-gear-and-bearing-pullerinuse.(ChevroletMotorDi-visionof GeneralMotorsCorporation) FIG.6-7.RemOvingmainshaftfromb'ansmissionwithspecialremoving-and-replacingtool.(ChevroletMotorDivision of GeneralMotorsCorporation) lugswiththemain-shaftsplines.Turnthetoolhandlessothat the mainshaftisforcedoutoftherearbearing.Removethetooland takethemain shaft outof the frontend of the case. Shift th'\lsecond-speed gear into the synchronizing drum.Remove theassembly,first-and-reverseslidinggear,andthesecond-[158]t\ \ \ StandardTmnsmis8ionandOverdriveService57 speedgearfromthecaseasaunit.Takethesecond-speed-gear thrust washer fromthe case. Expandtherear-bearinglockringwithaspecialtool(Fig.6-8), andtapthebearingintothecase.Tapontheouter-bearingrace. Removethecountershaftby drivingit fromthe reartothefront ofthecasewithasoft-steeldrift.Removecountergearandthrust washers.Driveoutthereverse-idler-shaftexpansionplugfromthe insideofthecasewithahook-nosedpunch.Drivetheidler-shaft lockpin into the shaft. This pin isshorter in length than the diameter FIG.6-8.Usingspecialexpanderon rearbearinglockring.(Chevrolet MotorDivisionofGeneralMotors Corpomtion) FIG.6-9.Usingspecialwrenchtore-moveretainingnutonclutch-gear shaft.(ChevroletMotorDivisionof GeneralMotorsCorpomtion ) oftheshaftsothattheshaftmayberemovedwhilethepinisin theshaft.Donotturntheshaftwhileremovingit,forthismight allowthe pintodropdown between the idler-shaft bushingswhere itwouldwedge.Removereverse-idlershaft and thrust washers. Disassembletheclutchgearbyclampingtheshaftinthesoft jawsofaviseandusingaspecialwrench(Fig.6-9 ).Removethe bearingfromtheshaftbyusingthespecialpressplateoverthe gearandagainstthebearing,pressingtheshaftoutwithanarbor press(Fig.6-10).Donotattempttodrivetheshaftoutofthe bearing asthis will damage the bearing. Disassemblethesynchronizingdrumbyremovingthesecond-speed gear and first-and-reverse sliding gear. Turn the synchronizing [159]

AutomotiveTmnsmissionsandPowerTrains ringinthedrumuntiltheendsofthesynchronizing-ringretainers canbeseenthroughtheslotinthedrumsleeve.Usespecialpliers toexpandtheretainersot1latthesynchronizingringcanbere-moved(Fig. 6-11). 2.F md.Late-modelFord transmissions(Figs.6-12 and 6-13 )are disassembledbytakingoutthecapscrewsandlooseningtheex-FIG.6-10.Removingbearingfrom clutch-gearshaft.(ChevroletMotorDi-visionof GenetalMotorsCorporation) FIG.6-11.Usingspecialpliersto expandretainersothatsynchroniz-ingringmaybedetached.(Chev-roletMotorDivisionofGeneral MotorsCorporation) tensionfromtherearofthecase,turningitone-quarterturn,so thatthecountershaftcanberemoved.Thecountershaftisdriven outtherearwithadmnmyshaft(shorterthanthecountershaft). Thecountershaftgears,withdummyshaftholdingtheminalign-ment,willdroptothebottom of thecase.Tapthe extensionlightly to pull it fromthecase.The main-shaft assembly willcome with it. Donotlosethefrontbearingrollers.Separatecountershaftgears, bearingrollers,spacers,anddummyshaft.Thereverse idlercanremovedbydrivingtheshaftfromthecasewitha [160]t\ \ \ StandardTransmissionandOverdriveService ....I "' .... >.. Ol

.s ;::l u [161] S1 [lp2] 00 AutomotiveTransmissionsandPowerTrains w &0 ----_..(111.11

I StandardTransmissionandOverdriveServiceS8 drift.Themain-shaftassemblyisdisassembledbyremovingthe snapring,tappingthemainshaftoutoftheextensionwithlight hammerblows,andthentakingthepartsofftheshaft.Theparts are held in place with snap rings. 3.Plymouth.TransmissionsusedinPlymouthsinrecentyears (Fig.6-14)aredisassembledasfollows:Removethespeedometer drivepinion,selector-balI-springscrews,andcoverassembly.Turn thetransmissionoverandremovetheselectorballs.Useaspecial pullertoremovethemain-shaftflangeandbrakedrum.Takeout shifter-forkguiderail.Then,putthegearsinneutralandremove thelockscrewsandshiftforks.Takeoutthe lowershifter-rail plug and remove the shifter rails through the front. Liftouttheshifterforksandthen removethe extensionwiththe main-shaftassembly.Handletheassemblycarefullytopreventdis-assemblyofthe synchronizerclutch.Takeoffthesnap ring sothat thesynchronizerunitandsecondandlowgearswillcomeoff.Re-movetherear-bearingsnapringandpullthemainshaftfromthe extension.Useaspecialarbortodrivethecountershaftfromrear ofthecase.Pickthekeyout ofthe shaftasit clears,and leavethe arborinplacetokeepthebearingrollersfromdroppingout.Re-movethe main-drive pinion and bearing assembly,take offthesnap ringandmain-gearbearing rollers.Then removethesnap ringand bearing.Thecountershaftgearsetmaynowbeliftedfromthe case.Thereverse-idlergearshaftmaybedrivenouttherearof the case with a special arbor. 58.InspectionoftransmissionpartsAfterthetransmissionisdis-assembled,allpartsshouldbecleanedandcarefullyinspectedas explained in the following paragraphs. 1.Ballbearings.Washbearingsincleaningsolventtoremove oldlubricantand dirt(except forsealed bearingswhich should not bewashed).After abearing iswashed,it should beblown dry with compressedair.Donotspinthebearingwhendryingitsincethis maydamagetheraces.Holdittokeepitfromturning.Examine bearingsforcrackedraces,damagedballs,andwear.Putoilon bearingballsandturnbearingslowlyby hand.If abearingturns roughly,ifracesareloose,orif theballsorracesarediscolored (blue- or straw-colored)fromoverheating,they should be replaced. 2.Rollerbearings.Examinetherollerscarefullyaftertheyhave [163] 58 "'--[164] AutomotiveTmnsmissionsandPowerTrains .11._---- :: \ StandardTransmissionandOverdriveService58 58AutomotiveTransmissionsandPowerTrains beencleaned.Rollersthatareworn,cracked,chipped,or that have Batspotsshouldbereplaced.Examineracesinwhichrollersturn and replace any part that shows signs of wear. S.Gearsandshafts.Examinethegearsandgearteethcarefully. Checkforworn,burred,orbrokenteethandfortonshaftor slidingsleeve.Do not confusetoolmarksleft in manufacturingthe gearswithactualscoresornicks.Trythetofsplinedgearson shaft or sliding sleeve.If t istoo looseor if gear teeth are damaged, thegearshouldbereplaced.Also,if thesplinedshaftorsleeveis worn,itwillrequire replacement.On theother hand, if thesplines arebatteredsothegeardoesnoteasilyslipbackandforthonthe splines,youmaybeabletosmoothdownburrsandimprovethe t by using an oil stone. Notetheconditionofshaftsthatrideonrollersorturninbush-ings.If thebearingsurfaceontheendoftheshaftisworn,the shaft should be replaced. Inspecttheconicalsurfacesofgearsaswellassynchronizing ringsforscoresor burrs.If these parts show wear or roughness, they shouldbereplaced.Itisnotrecommendedthatanyattemptbe madetopolishawayroughnessonthesepartssincethiswould changetheanglesorclearancesandtherebypreventnormal synchronizingactionwhenshiftsaremadeintosecondandhigh. Onecheckforwearofthesepartsistoplacethecontactingsur-facestogether inthe positionsthey wouldtake whenoperating and thentrytorockthem.If thepartsdonottsnuglytogether,re-placement should be made. 4.Transmissioncase.Cleancasethoroughlyandcheckitfor cracks.Inspectthefrontmountingfaceforburrsthatwould preventsquaremounting withtheclutchhousing.Burrsshouldbe knockedoffwith afine-cutfile.Oil sealsin placeinthe caseshould be checked and if worn orshowing signsof leakage,they shouldbe replaced.Boltholesinthecaseshouldbecheckedforstripped threads. 5.Snaprings,oilseals,gaskets.Suchpartsassnaprings,oil seals,andgasketsshouldbecarefullyinspectedanddiscardedif theyshowanysignsofwearordamage.Newgasketsshouldbe usedwhenthetransmissionisreassembledtoguardagainstoil leakage. [166] \ \ \ StandardTransmissionandOverdriveService59 6.Shiftermechanism.Shifterforksoryokesthatarebentor otherwisedamagedshouldbe replacedsincethiswould causehard shifting.Likewise,theconditionoftheshifterinterlockshouldbe noted and defective parts replaced. 7.Checkingfortransmissioncasemisalignment.Ifthetrans-missionisnoisyandjumpsoutofhighgear,thereisapossibility thatmisalignmentexistsbetweenthetransmissioncaseandengine block.Thiscanbecheckedwiththetransmissionandclutchoff theenginebyusingaspecialalignment-indicatortool,suchas showninFig.3-26,todeterminewhethertheholeintheclutch housingisoffcenter with the flywheel.The same indicator can then beusedtodeterminewhetherthefaceofthehOUSingisinalign-ment.Correctioninvolvesshiftingthehousing(afterdrillingout thedowel-pinholestoalargersize)and,possibly,shimmingbe-tweenthehousingandengine-blockattachingboltstoachieve alignment. 59.AssemblyoftransmissionTheassemblyofatransmissionis essentiallythereverseofdisassembly.Duringreassembly,allparts shouldbelubricatedastheyarereplaced.Thisnotonlyassures aninitialsupplyoflubricanttoallvitalpartsbutisalsohelpful inthereassemblyprocedure.Forinstance,atraceofgreaseona washerwillcauseittostickintoplaceonthecasewhiletheshaft isbeinginserted.Newgaskets,oilseals,and snapringsareusually specifiedbythemanufacturerwhenatransmissionhasbeendis-assembled and isbeing reassembled.Typical reassembly procedures follow. 1.Chevrolet.Lubricateandinstallthereverseidlerandthrust washers.Chamfered-toothgeargoestowardtherear.Installthe shaft,makingsurethattheshaftholelinesupwiththepinholein the case.Coat the new pin with Permatex or similar sealer and drive itaboutY16inchbeyond flushwiththecase.Peentheholeslightly sothatthepinwillnotworkout.Installexpansionplugsinthe shaftholes.Putthecountergearinthecasewiththefrontthrust washer.Feedaspecialassemblytool,taperedendfirst,infrom thefrontofthecase.Followitwiththecountershaft.Thetool alignsthepartsfortheshaft.Asthetoolnearstherear,installthe thrustwasher.Makesurethattheflatonforwardendoftheshaft [167} S9AutomotiveTransmissionsandPowerTrains ishorizontalandattopasitcomesoutthefrontofthecase.This Hatengagesinclutch housing whentransmissionisinstalledonthe car. Installtherear-bearingsnapring,expanditwithatool,andtap thebearingintoplace untilthesnap ringwillseat intheundercut whenthetoolisremoved.Installsynchronizerringsandretainers incounterboresintheendsoftheclutchsleeve,andthenplace first-and-reversegearonthesecond-and-thirdclutch.Meshthe clutchteethofthesecondgearwiththeinternalsplinesofthe second-and-third clutch. Placethethrustwasherontheback faceof thesecondgearand installthesecond-and-third-clutchassemblyinthecase.Lineup thethrustwasherandpushthemainshaftintotheClutchsleeve asfaraspossible,pickingupthesecondgearandwasher.Make surethatthelugsonthefrontsynchronizeralignwiththemain-shaftsplines.Attacharear-bearingsupportanduseaspecialre-placingtooltocompletereplacementofshaft,forcingtheshaftin untilitseatsontherearbearing.Putgreaseinthepilotholein themaingearandinstall14rollers.Thenputthemaingearand bearinginthecase,tappingtheouterraceofthebearinginto positionwithsoftdriftuntilthelockringseats.Synchronizing ring lugsmustalignwiththeslotsbetweentheclutchteeth. Finally,installthemain-gearbearingretainer,usinganew gasket,makingsurethattheoilslotsalign.Thespeedometergear, universal-jointspacer,andfrontyokemaythenbeputon.Install the gearshift housing. 2.Ford.Ingeneral,reassembly isthe reverse of disassembly.Use adummyshafttoassemblethecounters haftgears,bearings,and thrustwashers.Installthereverseidlerand shaft,making surethat thepinholesintheshaftandthecasealign.Put thepininplace. Installthemainbearingandretaineronthefrontofthecase.In-stallthesynchronizerblockspringsateachendofthehub,place theblockson the hub, and push the hub inside the sleeve.Place the synchronizerringontheassembly,makingsurethattheslotsalign withtheblocks.Useaspecialtooltoinstalltherear bushing in the transmissionextensionandtheoilsealintheendoftheextension. Put themain-shaftrearbearing Ontheshaftand press it intoplace. Putthe gearkeyandgearontheshaftandsecure withthe100Kring.Theninstallthe slidinggear,intermediategear, .[168]\ ..../\ \ \ StandardTransmissionandOverdriveService60 and synchronizerassemblyand securethemwith asnap ring.Place themain-shaftassemblyintheextensionandsecureitwithasnap ring.Useanewgasketonthe frontoftheextensionand install the extensiononthecase.Becarefultoavoiddisplacingthebearing rollerswhenthefrontendofthemainshaftentersthepilotinthe main gear. Turn the extension sothat the countershaft may be installed.This operationrequiresanaligning tool,which ispushed through bythe shaft.Makesurethattheshaft-pinholealignswiththecase-pin hole.Installthepin.Then,turntheextensionintopositionand secureitwithbolts.Installthegearshifthousing,usinganew gasket. 3.Plymouth.Placethecountershaft-gearthrustwashersinto positionwithsteelwashersnexttotherollersandbronzenextto thecase.Useaspecialtooltoinstalltheoilsealintherearendof theextension.Assemblethesynchronizerunit.Placeonebent-up endofthespringintothepocketof theshiftingplate.Theninstall thebent-upendoftheotherspringintothepocketofthesame plateontheoppositesideofthesynchronizer.Finally,installthe synchronizerunitonthemainshaft.Installtheshifterrailsand gearshift housing. 60.Steering-columngearshiftmechanismThesteering-column gearshift mechanism,together with the linkagesto the transmission, isdifferently constructed foreach model of vehicle,and few general directionsforitsadjustment,disassembly,andassemblycanbe given.Forspecificinstructionsrefertothevehicleshopmanual. Figures4-11to4-15illustratetypicalgearshiftmechanisms,from whichanideaoftherelationshipofpartsmaybegained.Figure 6-15illustratestherelationshipofpartsonasteering-columngear-shiftmechanismthat isdirectlylinkedtothetransmissionwithout vacuum booster or other shifter aid. Adjustmentof linkagesmust becorrecttoallowproper selection ofgearsandcompletionofgearshifts.Onthetypeofshifter mechanismshown inFig.6-15,two adjustments are required.These are the lower selector-rod adjustment, which determines the vertical distancebetweenthegearshiftleverandthesteeringwheel,and thelowercontrol-rodadjustment,whichdeterminestheradial position of the gearshift lever. [1691 ! } 60AutomotiveTransmissionsandPowerTrains Theselector-rodadjustment ismadeby removingthecotterand throughpin(A inFig.6-15)andturningtheadjustmentscrewB. Thetransmissionmustbeinneutral.Mteradjustmentismade, securethescrewwithpin,makingsurethewavewasherinside leverCisin place.The pin must passthrough the hole in the wave washer. FIG.6-15.Relationshipofpartsinsteering-columngearshiftmechanism. (OldsmobileDivision of GeneralMotorsCorporation) Thelowercontrol-rodadjustmentismadebyusingaspecial locatinggaugeassembledaroundthelowerendofthesteering column.Thelowercontrolshiftrodisfirstdisconnectedfromthe transmissionshiftleverbyremovingtheclevispin.Thegaugeis then placed around the steering columnsothat the slotted opening inthegaugeHtsaroundthelowerlever.Withthetransmissionin neutral,theclevisisadjusteduntiltheclevispinenterstheclevis and transmission shift lever freely. Linkage onanothergearshift-linkagearrangement areshown\ mFig.6-16.Onthissystem,the gear selectorrodisad-[170]\ \ \ \. StandardTransmissionandOve1'driveService61 justedfirst.Thelocknutontheselectorrodisloosened,andthen theadjustingnutistighteneduntilallplayoftherodistakenup, Thentheadjustingnutshouldbebackedoffone-halfturnfor clearanceandthe lockingnuttightened,Next,thegearshiftcontrol rodshouldbeadjusted,ifnecessary,tochangethepositionofthe gearshiftlever(whichshouldbe horizontalwhenthetransmission isinneutral ),Tochangethegearshift-leverposition,loosenthe lock bolt on the upper leverat the lower end ofthe steel'ing column asshowninFig,6-16.Locatethegearshift levercorrectlyand then tighten the lock bolt. FIG.6-16.Gearshiftlinkageadjustment.(PlymouthDivisionofChrysler Corporation) Lubricatepivotpointsorpointsofwearwherebindingcould occur,withappropriateoilorgreaserecommendedbythecar manufacturer.Usuallyafewdropsoflightengineoilonthepivot points is all that is required. 61.OverdriveserviceOverdrivedisassemblyandreassembly variesfrommodeltomodel.Whenworkingonaspecificmodel, theapplicableshopmanualshouldbefollowedcarefully.Dis-assemblyofalater-typeoverdriveused(withslightvariations) onsuchcarsasStudebaker,Ford,Packard,Kaiser,Frazer,and Nashisdetailedbelow.(RefertoFig.5-9foranexplodedview of thisunit.) [171] 61AutomotiveTransmissionsandPowerTrains 1.Disassembly. With transmission and overdrive assembly offthe car and mounted on transmission stand, disassemble as follows: a.Removecompanion-flangenutandflangefromendofshaft with specialholdingtooland puller. b.DiscoIDlectwiresandtakeofflock-outswitchandgovernor (Fig.6-17).Governormustbe unscrewed fromhousing. c.Driveouttaperedlocatingpin(1inFig.6-18)andpullshift shaftoutasfaraspossibletodisengagetheoperatingcam FIG.6-17.Overdriveontransmissionshowingwire(1 )betweengovernor(2) and lockoutswitch(3 ) .(Studebaker-PackardCorporation) fromtheshiftrail.Thenremovethefourcapscrewsholding theoverdrive housingtothetransmissioncase.Taptheend of the overdrive shaft lightly with alead hammer while removing thehousingsotheshaftwillnotcomeoffwiththehousing and spill the freewheeling rollers. d.Holdtheadapterplatetothecaseby replacingcapscrewin upperrighthole.Thenremovetheshift-railreverse-lockup spring,shift lever,shift shaft,and shaftoilseal.Now,removal oftherearoilsealpermits removalofthetwosnapringsand overdrive-shaft rearbearing. e.Rempvethespeedometerandgovernordrivegearsfromthe [172]\ \ \ StandardTransmissionandOverdriveService61 FIG.6-18.Removinglocatingpin(1)soshiftlever(2)withshiftshaft(3) canbepulledoutfarenoughtodisengageoperatingcamfromshiftrail. (Studebaker-PackardCorporation.) FIG.6-19.Holdinghandunderassemblytocatchrollersasthemainshaftis removed.(Studebaker-PackardCorporation) shaft.Theoverdrivemainshaftcannowbepulledout.Hold onehandundertheassemblytocatchrollersastheydrop out(Fig.6-19). f.Ringgearcannowbetakenofftheoverdriveshaftbyre-moving the large snap ring. [173] 61 AutomotiveTmnsmissionsandPowerTmins FIG.6-20.Removingretainingclipholdingfree-wheelingunitinplace. (Studebaker-PackardCorporation) FIC.6-21.Separatingfreewheelingunitfrompinion-cageassemblybyremov-ingretainingclip.(Studebaker-PackardCorporation) g.Withfreewheelingrollersoutofthecage,removetheretain-ingclip(Fig.6-20),andtakeoffthefreewheelingunitand pinion-cageassemblyfromthetransmission main shaft. h.Tosepflratethefreewheelingunitandpinion-cageassembly, take out the retaining clip(Fig. 6-21). I 174]/\ I \. StandardTransmissionandOverdriveService61 FIG.6-22.Removingsungearandshift-railassembly.(Studebaker-Packard Corporation) FIG.6-23.Removingsun-gearcoverplateandblockerassembly.(Studebaker-PackardCorporation) i.Overdrivesungear(Fig.6-22)andshift-railassemblycan nowbe removed.Shiftcollarcanbetakenoffsungearbyre-moving snap rings. i.Overdrivesolenoidcanbetakenoffbyremovingcapscrews and turning the solenoid one-fourth tum. [175] 61AutomotiveTransmissionsandPowerTrains k.Takeoutlargesnapringandthenpullsun-gearcoverplate and blocker assembly out(see Fig.6-23). l.If thetransmissionalsorequiresdisassembly,themainshaft, withadapterplateandgears,canbe removedasaunitfrom the transmission case. 2.Inspectionofparts.Inspectionofoverdrivepartsisvery similartoinspectionoftransmissionpartsasoutlinedin58.Note particularlytheconditionofoilseals,gears,andbearings.In addition, the electrical condition of the electrical components should benoted.Thatis,theoperationofthegovernor,solenoid,relay, andswitchesshouldbechecked.Thesechecksrequireelectrical FIG.6-24.Properpositionoftheblocker ringandpawlwhentheoverdriveis assembled.(Studebaker-PackardCor-poration) FIG.6-25.Proper positionofthe freewheelingretainersprings. ( Studebakel'-PackardCorpora-tion) testinginstrumentssuchasaredescribedinanotherbookinthe McGraw-HillAutomotiveMechanicsSeries(AutomotiveElectdcal Equipment) . 3.Reassembly of overdrive.Essentially,reassembly isthe reverse ofdisassembly.Whenreplacingtherollers,usealittleLubriplate orwheel-bearinggreasetoholdtheminpositionduringtheas-semblyprocess.Also,besuretousenewgaskets.Wheninstalling thesun-gearblockerassembly,makesuretheblockerringand pawlareproperlypositionedasshowninFig.6-24.Also,make surethatthefreewheelingretainerspringsareinstalledcorrectly. Theyshouldbesoinstalledthatwhenviewedfromtherear,the endsoftHespringswhichareoutsideshouldpaintin aclockwise direction \( Fig. 6-25). [176]r, \. StandardTransmissionandOverdriveService CHAPTERCHECKUP NOTE:Sincethefollowingisachapterreviewtest,youshouldreview the chapter before taking it. Someautomotivemechanicsaretransmissionspecialistsandspenda greatpartoftheirtimeworkingontransmissions.However,anygood, all-roundautomotivemechanicshouldknowhowtodiagnosetrans-missiontroubleandcorrectit,ifnecessary,byremovinganddis-assemblingthetransmission.Thechapteryouhavejustfinishedde-scribesdifferenttransmissiontroubles,methodsoftrackingdowntheir causes,andrepairprocedurestoeliminatethesecauses.Now,inthe checkupthatfollows,thesedifferenttransmissiontroublesandservices arehigh-lighted.Thus,thecheckupwillhelpyoutofixthesetroubles andservicesinyourmind.If youarenotsureaboutthecorrectanswer toanyof thequestions,turnback intothechapter andreviewthe pages that willanswer them foryou.Write down the answers in your notebook. Thisactofwritingdowntheanswershelpsyoutoremember,andthe notebookwillbecomeavaluablesourceofinformationyoucanrefer to quickly in the future. CompletingtheSentences Thesentencesbelowareincomplete.Aftereachsentencethereare severalwordsorphrases,onlyoneofwhichwillcorrectlycompletethe sentence.Writeeachsentencedowninyournotebook,selectingthe proper word or phrase to complete it correctly. 1.Improperly adjustedgearshift linkage could causehardshifting intogearclutchslippagenoise inneutral 2.Misalignmentbetweenthetransmissionandengineismostaptto causenopowerthroughtransmissiontransmissionslipping out of high geartransmission slipping out of first 3.Transmissionnoiseinneutralcouldresultfrommisadfusted gearlinkageworngearswornspeedometergears loosepropeller shaft 4.Clashingofgearswhenshiftingintohighcouldresultfrom enginemisalignmentdrivekeyshearedadefective synchronizer 5.Failureoftheoverdrivetogointooverdrivecouldbedueto incorrectclutch-pedaladfustmentdefectinelectriccircuit gearshiftlinkagemisadjusted 6.Pilotorguidepinsareusedin damagetotheclutchshaft transmissionremovaltoprevent clutchfrictiondisk countershaftgearshiftlinkage C177] AutomotiveTransmissionsandPowerTrains 7.Transmissionnoiseingear could resultfroma bent shifterfork a wornreartransmissionbearingclutchnotreleasing 8.Ballbearingswithdiscoloredorcrackedballsorracesshould berelubricatedreplacedreoiledrecleaned TroublesandServiceProcedures Inthefollowing,youshouldwritedowninyournotebookthetrouble causesandserviceproceduresaskedfor.Donotcopytheprocedures fromthe book;trytowritethem in your own words.Writingthemdown inyourownwordswillbeofgreathelptoyoubecausethiswillenable youtorememberthembetter;youwilltherebybegreatlybenefited when you go into the automotive shop. 1.Listconditionsthatcouldresultfromthegearshiftlinkagebeing out of adjustment. 2.List conditionsthat could result fromworngearsinthetransmission. 3.Listconditionsthatcouldresultfromlackoflubricationinthe transmissionand gearshift linkage. 4.List conditionsthat could cause hard shifting. 5.Listconditionsthatcouldcausethetransmissiontoslipout ofgear. 6.List possible causesofnoise in the transmission. 7.Describetheelectricalcheckstobemadeif theoverdrivedoesnot gointooverdrive. 8.Describetheelectricalcheckstobemadeiftheoverdrivedoesnot come out of overdrive. 9.Describetheelectricalcheckstobe made ifshift intoreversecannot bemadeandoverdrivedashknobisjammedinOD position. 10.Refertotheshopmanual of aspecific-modelcar and list the stepsto betakentoremove,disassemble,reassemble,andreplacethe transmission. 11.Listthecheckstobemadeonthepartsofadisassembledtrans-mission. 12.Refer totheshopmanual of aspecific-modelcar and listthe steps to be takentoadjust thegearshift linkage. SUGGESTIONSFORFURTHERSTUDY When youarein theautomotiveserviceshop,pay specialattentionto themenworkingontransmissionssoyoucanlearnmoreabouthow varioustransmission-repairandreadjustmentjobsaredone.Noticethe specialtoolsrequiredandhowthesetoolsareused.Studydifferentcar-manufacturers'manualsinordertobecomemorefamiliarwithdifferent transmissinconstructionsandservicingprocedures.Besuretowrite downiny6urnotebookanyimportant factsyoucomeacrosssoyouwill have arecord of them. [1781:'\ 7:Transmissions with fluid couplings THEPURPOSEofthischapteristodescribetheoperationof Ruidcouplingsand,inaddition,toexplaintheconstructionand operation of transmissionsusing Ruidcouplings. Formanyyears,engineersandinventorshavesearchedfor meansofmakinggearshiftingeasier.Theintroductionofsyn-chronizingdevicessuchasthesynchromeshwasoneresultoftheir efforts;thismechanismmakesitvirtuallyimpossibletoclashgears whenshiftingintosecondorhigh.However,itwasstillnecessary tooperateaclutchtointerrupttheRowofpowerandtomove alevertoshift the gearsfromoneto another meshing position. Inrecentyears,automaticdeviceshavebeenbroughtoutwhich eliminate thisjob.That is,the gear ratio through the transmission is changedsemiautomaticallyorautomaticallyinaccordancewith car and engine speed and the driver's wishes. Withthistypeofgear-ratio-changingdevice,thepowerflow throughthetransmissionmuststillbeinterrupted,eventhough momentarily,sothegear-ratiochangecanbe achieved.Thus,there istheproblemofmakingthispower-Rowinterruptionandreap-plicationsmoothly.If itisdonetooabruptly,theoccupantsofthe carwillbejarred.Worse,thepower-traincomponentsandengine willbesubjectedtoshockstrainsthat,sooneror later,might cause failureof some part.Toeliminate thissortof sudden jarring change in the power-Row pattern, fluidcouplings were introduced. Thefluidcouplingcouplestheenginewiththepowertrain, andsinceittransmitsengine-poweroutput through aRuid,it tends tosmoothoutanyshock-loadingorunloadingeffectproduced bytheactionoftheautomaticgear-ratiochanging device.Thatis, it absorbstheshockof any suddenchange and cushionsthe engine and power train fromthe shock. [179] 62 AutomotiveTransmissionsandPowerTrains 62.HydraulicsBeforewegetintoadiscussionofthefluid couplingandthevarioustransmissionswithwhichitisused,we shouldfirstunderstandsomethingabouthydraulics.Hydraulicsis thescienceofliquids,suchaswateroroil.Ourspecialinterest,so farasautomatictransmissionsisconcerned,isinthepressuresthat can be exerted by liquids. 1.Incompressibilityofliquids.If agas,suchasair,isputunder pressure,itcanbecompressedintoasmallervolume(Fig.GASCANBECOMPRESSED LIQUIDCANNOTBECOMPRESSED FIG.7-l.Cascanbecompressedwhenpressureisapplied.Liquid,however, cannotbecompressedbyapplicationofpressure.(PontiacMotorDivisionof GeneralMotorsCorporation) However,applyingpressuretoaliquidwillnotcauseittocom-press; it stays the same volume. 2.Transmittingmotionbyliquid.Sinceliquidisnotcom-pressible,motionmaybetransmittedbyliquid.Forexample,Fig. 7 -2showstwopistonsinacylinderwithaliquidbetweenthem. Whentheapplyingpistonismovedintothecylinder8inches,as shown,thentheoutputpistonwillbepushedalongthecylinder thesame, distance.Intheillustration,youcouldsubstituteasolid connectifngrodbetweenpistonAandpistonBandgetthesame P8D] \ \ \, TransmissionswithFluidCouplings62 FIG.7-2.Motioncanbetransmittedbyliquids.WhentheapplyingpistonA ismoved8inches,thentheoutputpistonisalsomoved8inches.(Pontiac MotorDivision of GeneralMotorsCorporation) OUTPUT FIG.7-3.Motionmaybetransmittedthroughatubefromonecylindertoan-otherbyhydraulicpressure.(PontiacMotorDivisionofGeneralMotorsCt)T-poration) result.But theadvantageofsuchasystemisthat youcan transmit motionbetweencylindersbyatube(Fig.7-3).InFig.7-3,asthe applying piston ismoved,liquid isforcedout of cylinder A,through the tube,and into cylinder B.Thiscausesthe output piston to move in its[181] 62AutomotiveTransmissionsandPowerTrains 100lBS. PERsq.IH. 100lBS. PERSQ. l\t. 100 lBS. PERsq.IH. FIG.7-4.ThepressureappliedtoaliquidistransmittedequallyinaUdirec-tions.(PontiacMotorDivisionofGeneralMotorsCorporation). 100LB ,SQ'NtH PISTONAREA 100La 2. SQ'NCHES PISTONAREA FIG.7-5.The hydraulicpressure(inpsi)in the systemisdetermined by divid-ingtheapplyingforce(pounds)bythearea(squareinches)oftheapplying piston.(PontiacMotorDivisionofGeneralMotorsCorporation) 3.Transmittingpressurebyliquid.Thepressureappliedtoa liquidistransmittedbytheliquidinalldirectionsandtoevery partoftheliquid.Forexample(Fig.7-4),whenapistonwith1 squareinphofareaappliesaforceof100poundsonaliquid,the ontheliquidis100psi(poundspersquareinch).This [182] j\ \ \. TmnsmissionswithFluidCouplings62 pressurewillberegisteredthroughout theentirehydraulicsystem. If theareaofthepistonis2squareinchesand thepistonappliesa forceof100pounds,thenthepressure isonly 50psi(Fig.7-5). Withaninput-outputsystem(Fig.7-6),wecandeterminethe forceappliedtoanyoutputpistonbymultiplyingthepressurein poundspersquareinchbytheareaof theoutput pistoninsquare inches.For example,thepl'essureshowninFig.7-6is100psi.The outputpistontothelefthasanareaof0.5squareinch.Thus,the output forceon thispiston is100times 0.5 or 50 pounds.The center piston hasanareaof1 square inch and itsoutput forceistherefore OUTPUTFORCE 50 LB OUTPUTFORCE 100LB OUTPUTFORCE 200LB FIG.7-6.Theforce(pounds)appliedtotheoutputpistonisthepressurein thesystem in psitimesthe area(squareinches)ofthe output piston.(Pontiac MotorDivision of GeneralMotorsCorporation) 100pounds.Theright-handpistonhasanareaof2squareinches anditsoutput forceistherefore 200pounds(100X2).The bigger theoutputpiston,thegreatertheoutputforce.If theareaofthe pistonwere100squareinches,forexample,thentheoutputforce wouldbe10,000pounds.Likewise,thehigherthehydraulicpres-sure,thegreatertheoutputforce.If thehydraulicpressureonthe 2-square-inchpistonwentupto1,000psi,thenthe output forceon the piston would be 2,000 pounds. Inalltheillustrationsabove,apiston-cylinderarrangementhas beenshownasthe meansof prodUCingthe pressure.However,any sortofpumpcanbeused.Wewilllearn,instudyingthevarious [183]

AutomotiveTransmissionsandPowerTrains automatictransmissions,that several typesof pump havebeen used (gear, rotor, vane). 4.Hydraulicvalves.Asimpleapplicationoftheabove principles isfoundinapressure-regulatingvalve(Fig.7-7).Thevalveis spring-loadedandisessentiallyasmallpistonthatcanmoveback andforthinacylinder.Thevalveactstoproduceaconstant pressurefromavariable-pressuresource.Forexample,suppose thepressuresourceisanoilpumpbeingdrivenbyanautomobile engine.Whentheengineisoperatingathighspeed,theoilpump isalsobeingoperatedathighspeedandwillproduceahigh pressure.Thepressure-regulatingvalvereducesthispressuretoa preset value, however, in the following manner. Pump pressure valve

Output:: pressure+-'IReturnline 'i'toreservoir A

Valvemoved fariqhtto uncover =returnline Itoreservoir B FIG.7-7.Apressure-regulatingvalve(A).Aspumppressureincreases,the spring-loadedvalvemovesbackagainstspringpressure(asatB),dumping moreoftheoilfromthepumpintothereturnline.Thismaintainsaconstant outputpressure. Asthe pressuregoesup,there isanincreasing forceon the valve. Finally,whenthepresetvalueisreached,theoilpressureisgreat enough(in pounds per square inch)to overcome the spring pressure. Thevalveismovedbackinitscylinder.Asitmovesback,itun-coversanopening,orport,whichisconnectedtoalow-pressure returnlinetotheoilreservoir.Now,part oftheoilfromthepump canflowthroughthisreturnline.Thisreducesthepressuresothat thevalvestartsforwardagain(movedbythespringpressure). However,asitmovesforward,itpartlyshutsofftheporttothe returnline.Sincelessoilcannowescape,theoilpressuregoesup andthevalveisagainmovedback.Actually,thevalvedoesnot normallymoveback and forth,asdescribed above.Instead,it seeks andfindsthepositionatwhichtheoilpressurejustbalancesthe springpressure.Then,if theoilpressurechanges(due toachange inpumpspeed),thevalvepositionwillchange.Inaction,the valvemaintainsaconstantoutputpressurebydumpingasmaller [184]1\\ \ \ \ TransmissionswithFluidCouplings62 orgreaterpartoftheoilfromthepump.Aspumppressuregoes up,forexample(whichmeansthepumpdeliversmoreoil),the valvemovesbacktoopentheportwiderandpermitmoreofthe oil to How into the return line. 5.Balancedvalve.Inautomatictransmissions,balancedvalves areusedtoproducepressurechangesthatareproportionaltothe movement of mechanical linkageortovariationsin spr