Some 1980 through 1983 Omegas, Cutlass Cieras and Firenzas equipped with a THM 125/125C transaxles may exhibit a no reverse or neutral to reverse delayed engagement condition.
To correct these conditions, two changes in the low and reverse clutch assembly were introduced in late March 1983. Refer to Figure 5. The low and reverse piston assembly is being produced with a third design lip seal retainer (Figure 1) and an oil displacement insert (Figure 2) was added to the low and reverse clutch assembly. This insert displaces oil and quickens the apply of the low and reverse clutch.
When servicing any 1980 through 1983 THM 125/125C transaxle for a no reverse or a neutral to reverse delayed engagement, refer to the following chart:
Type of Low and Condition Reverse Clutch Asm. Correction --------- ------------------- ---------- No reverse - Lip First Design Replace the low and reverse Reuiner has separated (Figure 3) clutch assembly with Service from the tow and reverse Package No. 8653915. Also piston assembly add the oil displacwnent insert (part no. 8643490)
Neutral to Reverse First Design Replace the low and reverse Delayed Engagement (Figure 3) clutch assambly with Service Package no. 8663915. Also add the oil displacement insen (part no. 8643490).
No Reverse - Lip Seal Second Design Replace the second design Retainer has separated (Figure 4) low and reverse piston with a from low and reverse third design low and reverse piston assembly piston (part no. 8653916)
Noutral to reverse Second Design Add the oil displacement Delayed Engagement (Figure 4) insert (part no. 8643490) to the low and reverse clutch assembly
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.