Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSPONTIAC1987J2000/SUNBIRD L4-121 2.0LREPAIR AND DIAGNOSISTECHNICAL SERVICE BULLETINSALL TECHNICAL SERVICE BULLETINSA/T - SLIPS IN 1ST OR NO 1ST GEAR
1987 Pontiac J2000/Sunbird L4-121 2.0L
A/T - Slips In 1st or No 1st Gear
1987 Pontiac J2000/Sunbird L4-121 2.0LSECTION A/T - Slips In 1st or No 1st Gear
89Pontiac23
Bulletin Number: 89-7-49
Reference Number: 977147
Publish Date: 11/89
Subject: SLIPS IN 1ST AND/OR NO 1ST GEAR (NEW FORWARD CLUTCH PISTON SEALS)
Models
Affected: 1980-89 ALL MODELS WITH 3T40 125C TRANSMISSION
BULLETIN COVERS:
New Forward clutch Piston seals (626, 627) made of Viton. These new Viton 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 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 seal can be used on all model year HYDRAMATIC 3T40 (THM 125C) transaxles.
SERVICE PARTS INFORMATION:
Refer to the following part number when ordering new Viton seals to service the Forward clutch assembly.
Part Number Description
8631986 Piston Seals (Viton), Forward Clutch
Current packages will be revised to contain new Viton 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.
Bulletin Number: 89-7-49
Reference Number: 977147
Publish Date: 11/89
Figure 1:
Subject: SLIPS IN 1ST AND/OR NO 1ST GEAR (NEW FORWARD CLUTCH PISTON SEALS)
Models
Affected: 1980-89 ALL MODELS WITH 3T40 125C TRANSMISSION
BULLETIN COVERS:
New Forward clutch Piston seals (626, 627) made of Viton. These new Viton 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 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 seal can be used on all model year HYDRAMATIC 3T40 (THM 125C) transaxles.
SERVICE PARTS INFORMATION:
Refer to the following part number when ordering new Viton seals to service the Forward clutch assembly.
Part Number Description
8631986 Piston Seals (Viton), Forward Clutch
Current packages will be revised to contain new Viton 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.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.