Some 1984 and some early 1985 THM 440-T4 transaxles may experience a no Torque Converter Clutch (TCC) apply or TCC shudder condition, which may be due to a cut TCC accumulator piston seal (See Illustration below).
To repair this condition a new TCC accumulator piston pin, piston and seal went into production on June 24, 1984 (Julian date 176).
When servicing any 1984 or early 1985 THM 440-T4 transaxles built before the above Julian date for a no TCC apply or TCC shudder, order service package 8646926.
Service package 8646926 contains the following:
1 - TCC ACCUMULATOR PISTON 1 - TCC ACCUMULATOR PISTON PlN I - TCC ACCUMULATOR PISTON SEAL
Refer to the appropriate service manual for proper installation procedures.
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.