A/T - Late 1988 GM 4T60/440T4 Changes

SIL: 89-13 (Apr)

SUBJECT: HYDRAMATIC

LATE 1988 GM CHANGES




In late 1988 General Motors changed the upper channel plate gasket. (See Figure A)

The new gasket connects the modulator port and the upper channel gaskets together. The change was made to prevent mis-assembly of the gaskets at the factory.

The new gasket will only retrofit back to mid-1985. The old gaskets can be purchased separately.

IMPORTANT
The new one-piece channel gasket CANNOT be used to service transaxles built before Julian Date 0II for 1985 models. If the new gasket is used on a previous channel plate, Park, Reverse and Neutral (PRN) fluid may enter the reverse servo feed circuit and apply the reverse bend.

Since the input clutch is applied in Park, the transaxle may be in Park and Reverse at the same time when Park is selected.