HARD OR HARSH 1-2 SHIFT ROLLED ACCUMULATOR SEAL

TRANSMISSION APPLICATIONS: SUBJECT:

1987 THM 125C (MD9) HARSH 1-2 SHIFT TRANSMISSION MODELS: VEHICLE APPLICATIONS:

ALL MODELS A, J, L, N, P Cars (Revised to Correct Date in Second Paragraph)

Bulletin Covers:

Vehicles equipped with a 1987 THM 125C built between the dates of April 13, 1987 through April 21, 1987 (Julian Dates 103-112), may have a rolled or misassembled 1-2 accumulator piston seal, resulting in a possible harsh 1-2 shift. These 1987 THM 125C Transaxles (Julian Dates 103-112) have a new design accumulator piston (flat inner surface) and a soft synthetic rubber 1- 2 accumulator piston seal that may be inadvertently misassembled.

DATE OF PRODUCTION CHANGE: (Figure 1) -------------------------

New design accumulator piston (flat inner surface) and synthetic rubber accumulator piston seal on all 1987 THM 125C Transaxles built April 13, 1987 (Julian Date 103) through April 21, 1987 (Julian Date 112).

SERVICE ACTION: (Figure 2) --------------

If a vehicle equipped with a 1987 THM 125C Transaxles built between Julian Dates 103-112 experiences a harsh 1-2 shift, examine the 1-2 accumulator piston and seal for damage or misassembly. If necessary, replace the Piston and seal with the original design accumulator piston (raised rib) and P.T.F.E. seal. These parts are not interchangeable.

SERVICE PARTS INFORMATION:

8631657 1-2 Accumulator Piston 8631895 1-2 Accumulator Piston Oil Seal Ring

SERVICE MANUAL REFERENCE:

Refer to the THM 125C Transaxle Unit Repair Section in the appropriate Service Manual.

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.