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 MANUALSPONTIAC1983J2000/SUNBIRD L4-121 2.0LREPAIR AND DIAGNOSISTECHNICAL SERVICE BULLETINSALL TECHNICAL SERVICE BULLETINSA/T - 3T40/THM 125C FORWARD DRUM DESIGN CHANGES
1983 Pontiac J2000/Sunbird L4-121 2.0L
A/T - 3T40/THM 125C Forward Drum Design Changes
1983 Pontiac J2000/Sunbird L4-121 2.0LSECTION A/T - 3T40/THM 125C Forward Drum Design Changes
SIL 89-6 (Feb)
HYDRA-MATIC 3T40/THM 125C
SUBJECT: Forward Drum Changes
A new design forward drum and thrust washer entered production November 3, 1987 (Julian date 344).
The new design forward drum contains a stamped channel which increases forward clutch feed. This provides a shorter neutral to drive engagement (See figure 1).
The new design forward drum can be used in all model THM 125/125C transmissions. Whenever the new design forward drum is used1 the new design bronze thrust washer must be installed (See Figure 1).
Part number for the new design bronze thrust washer is:
8664762
If the earlier style drum is used (built prior to Julian Date 344) and the plastic thrust washer needs replacement, it may be replaced with an interim design metal thrust washer.
Part number for the interim metal thrust washer is:
8652759
Package number 8664982 includes the new design forward drum, and new design thrust washer.
HYDRA-MATIC 3T40/THM 125C
SUBJECT: Forward Drum Changes
A new design forward drum and thrust washer entered production November 3, 1987 (Julian date 344).
The new design forward drum contains a stamped channel which increases forward clutch feed. This provides a shorter neutral to drive engagement (See figure 1).
The new design forward drum can be used in all model THM 125/125C transmissions. Whenever the new design forward drum is used1 the new design bronze thrust washer must be installed (See Figure 1).
Part number for the new design bronze thrust washer is:
8664762
If the earlier style drum is used (built prior to Julian Date 344) and the plastic thrust washer needs replacement, it may be replaced with an interim design metal thrust washer.
Part number for the interim metal thrust washer is:
8652759
Package number 8664982 includes the new design forward drum, and new design thrust washer.
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.