A/T - Revised Forward Clutch Piston Seals
89olds12SUBJECT SLIPS IN 1ST AND/OR NO 1ST GEAR (NEW
FORWARD CLUTCH PISTON SEALS)
MOOELS/YEARS ALL 1980-1990 MODELS EQUIPPED WITH
HYDRA-MATIC 3T40 (THM 125/125C) TRANSAXLE (RPO - MD9)
NUMBER: 90-T-20
CORP.REF.NO: 977147
DATE: November 1989
SECTION: 7A
Figure 1:
BULLETIN COVERS:
New Forward Clutch Piston Seals (626, 627) made of Viton(R). These new Viton(R) seals replace the currently used lip seals which may become brittle and take a permanent heat set (become flat) with high mileage, allowing possible leaks in the forward clutch (624). Refer to Figure 1.
DATE OF PRODUCTION CHANGE:
Viton(R) seals went into production for all Willow Run built HYDRA-MATIC 3T40 (THM 125C) transaxles October 6, 1989 (Julian Date 279).
SERVICE PROCEDURE:
This new Viton(R) seal can be used on all model year HYDRA-MATIC 3T40 (THM 125C) transaxles.
SERVICE PARTS INFORMATION:
Refer to the following part number when ordering new Viton(R) seals to service the Forward clutch assembly.
Part Number Description
8631986 Piston Seals (Viton(R)) Forward Clutch
Current packages will be revised to contain new Viton(R) seals. Parts are currently available from GMSPO.
SERVICE MANUAL REFERENCE:
Refer to the HYDRA-MATIC 3T40 (THM 125C) (MD9) Automatic Transaxle Unit repair section of your service manual whenever service of the Forward Clutch is necessary.