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4L60ENo 2nd, 4th and Reverse

Many 1997-99 4L60Es may lose reverse, 2nd and 4th gears. This is caused by a change in the manufacturingprocess for the sun gear reaction shell. During production, the radius of the area attaching the splines on theshell to the shell housing was reduced. This leads to a fatigue failure of the shell.

Technical Bulletin #578Transmission:

Subject:Application:Issue Date:

4L60ENo 2nd, 4th and reverse

January, 2003

Technical Bulletin #578

Copyright © 2003 ATRA. All Rights Reserved.SG ! Page 2 of 2

GM increased the radius of this area for added strength. To repair this condition, replace the shell. The part number for the updated shell is the same as the old shell. What’s more, GM didn’t purge the faulty parts frominventory, so you may not get the updated part when you order it.

The best way to tell if your part is the updated one is by checking the ID stamped inside the shell. The ID consists of a letter and three numbers. If your shell begins with the letters A or B, you have the old-style shell.The updated shells begin with the letters T or W.

The GM part number for the sun gear shell is 8683439.