DIY Transmission Fluid Exchange on Ford TorqShift

TransmissionsHow to build and use a heated and

pressurized system to exchange fluid in automatic transmissions

Prepared by greasyfingers, forum member on www.thedieselstop.com.

For educational use only; author takes no responsibility for the completeness and accuracy of the contents

Problem

• 2006 Ford F-350 with TorqShift 5r110W automatic transmission holds 17.5 qts of fluid between the transmission, torque converter, lines, and coolers

• Draining the pan only replaces 7.5 qts, leaving the bulk of the old fluid trapped in the torque converter and coolers

Common Solution• On typical automatic transmissions, a cooler line

flush (or, better termed “exchange”) is performed by the DIYer by starting the engine with one of the external fluid cooler lines disconnected and directed into a bucket

• As old fluid comes out the line, new fluid is poured into the dipstick filler tube until the fluid runs clear

• This method usually pumps the old fluid out of the torque converter, providing a complete exchange of the old fluid

Why a simple cooler line exchange doesn’t work for the TorqShift

transmission• There is an internal temperature regulator that

limits the external flow to the cooler until the fluid temp reaches operating temperature (~160 deg)

• Even at operating temp, the cooler line flush procedure will not work, since the fresh fluid being poured into the dipstick is cold, and cannot keep up with the rate at which old fluid is being pumped out when the regulator opens

• The torque convertor will not be flushed if attempting this procedure cold

Professional Solutions• Ford dealers and service garages may have the

heated fluid exhange equipment to connect to the cooler lines that will automatically exchange the old fluid with new fluid

• The service is costly• Mechanics have been known to incorrectly

perform this maintenance, or have no knowledge of it (the Ford factory service manual does not specify the requirement to exchange the fluid while at operating temperature)

The DIY Solution:

• Heated reservoir of 18 qts

• With air pressure applied, heated fluid is forced into the transmission as fast as it is pumped out

How it’s made:

• Starts with a 5-gallon capacity pressure vessel (old 20-lb propane tank works well)

How it’s made-Modify the tank

• Completely empty the tank• Remove fill valve• Purge LP gas out of tank!• Drill holes where needed for adding

pipe fittings• Weld threaded bosses to tank for fill port,

heating element, and temperature probe

How it’s made-Install Components

• Assemble pipe fittings for fill port, drain port, sight gauge, air inlet, and temperature probe

• Air test, and hydro test welds for leaks

How it’s made-Install Components, cont’d

• Install electric water heater element• Mount thermostat to side of tank, just

higher than the element

How it’s made-Mounting

• Attach tank to a suitable base, a plywood base in this case

How it’s made-Insulation

• To warm up faster, and prevent contact with hot surfaces, wrap the completed tank in insulation.

How it’s made-Wiring

• Wire the thermostat to the heating element

• Control the power to the thermostat with a switch

• Add indicator lights to tell when there is power to the thermostat, and when the thermostat is closed (actively heating)

• Connect a power cord with grounded plug, rated for 15A

Vehicle Modifications

• Locate cooler return line to transmission• Cut pipe, install flare nuts, and flare ends

of pipesInstall a union in the line during normal use

Exchange Instructions

• Preparation of Exchange Rig• Preparation of Vehicle• Exchange Procedure

Exchange Instructions-Preparation of Exchange Rig

1. Fill exchange rig with new transmission fluid, per manufacturer’s specs

2. Add one extra quart over the transmission capacity (18.5 qts for TorqShift)

3. Power up the exchange rig heater element4. Monitor temperature (~1/2 hr for 18.5 qts)5. Swirl the tank to ensure even heating since the fluid

below the element will not warm up quickly6. Adjust thermostat to maintain 170-180 deg7. Connect air supply with regulator set at 30 psi max

Exchange Instructions-Preparation of Vehicle

8. Engage parking brake, chock wheels9. Run engine in gear until transmission

and engine are at normal operating temperature (middle of the gauges)

10.Shut off engine11. Immediately initiate the following steps

before transmission cools off:

Exchange Instructions-Exchange Procedure

12.Drain oil in the transmission pan by removing the drain plug. Replace plug

13.Pour fluid into discharge bucket and make note of amount of fluid

Exchange Instructions-Exchange Procedure – Final connections to

vehicle14.Connect elbow fittings

to flares15.Run discharge hose

into discharge bucket16.Connect return hose to

drain valve on rig

Exchange Instructions-Exchange Procedure – cont’d

17. Restart engine18. Put into gear19. As fluid flows out of transmission discharge hose into discharge bucket, adjust

drain valve on rig to match that flow into the transmission. A design flaw with this sight gauge design draws air into the line due to a venturi effect, so an added shutoff valve must be closed on the gauge when draining the rig.

20. When the bucket has 17.5 qts of fluid in it, shut off the engine and the rig.21. Caution! Do not over-fill transmission, or fluid will come out the overflow

and/or dipstick tube. It is best to fill slower than the oil is pumped out, but not to allow the oil pan to go dry.

22. When nearly all fluid has drained from the rig, watch for air in the drain line and immediately shut off the valve, or pressurized air will violently blow fluid out the overflow and dipstick tubes on the transmision.

23. Shut off the engine when volume of drained fluid in discharge bucket reaches 17.5 qts.

24. Replace remote filter element.25. Remove the rig hoses and reinstall the union in the transmission cooler return line.

Restart vehicle, check for leaks in the union, and adjust fluid level on the dipstick with transmission in Park, and at normal operating temperature.