A 1984 through 1987 vehicle equipped with a THM 440-T4 transaxle may have an intermittent no reverse or locking in reverse condition until shifted to a forward range, prior to shifting into reverse ("unloading" the parking pawl). This condition may be caused by a "dent" on the parking pawl that does not allow the pawl to release until "unloaded".
Effective May 1, 1987 (Julian date 121) all 1987 THM 440-T4 transaxles were produced with parking pawl assemblies not having a "dent".
Remove transaxle and replace the Final Drive Internal Gear/Parking Pawl Assembly (#673) and Actuator Guide, Plunger and Spring Assembly (#709 - #711). Also inspect the Parking Gear for wear or damage and replace if necessary.
Part Number Description ----------- ----------- 8656372 Final Drive Internal Gear/Parking Pawl Assembly 8656689 Actuator Guide, Plunger and Spring Assembly 8644238 Parking Gear
Refer to appropriate Service Manual for repair information.
Before installing the replacement parts, inspect the new Final Drive Internal Gear/Parking Pawl Assembly to make sure it does not have a "dent".
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.