A/T - Intermittent No Reverse or Locks In Reverse
Number 87-7-37 Date 8/87Subject: INTERMITTENT NO REVERSE OR LOCKS IN REVERSE
1984-87 6000 AND BONNEVILLE MODELS EQUIPPED WITH THM 440-T4 TRANSAXLE
BULLETIN COVERS:
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".
Figure 1 - THM 440-T4 Transaxle Identification Information:
DATE OF PRODUCTION CHANGE: (Figure 1)
Effective May 1, 1987 (Julian date 121) all 1987 THM 440-T4 transaxles were produced with parking pawl assemblies not having a "dent"..
Figure 2 - Final Drive Internal Gear Assembly:
Figure 3 - Parking Lock Actuator Assembly:
SERVICE ACTION: (Figures 2 and 3)
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.
SERVICE PARTS INFORMATION:
Part
Number Description
8656372 Final Drive Internal Gear/Parking Pawl Assembly
8656689 Actuator Guide, Plunger and Spring Assembly
8644238 Parking Gear
SERVICE MANUAL REFERENCE:
Refer to appropriate Service Manual for repair information.
Figure 2 - Final Drive Internal Gear Assembly:
SERVICE NOTES: (Figure 2)
Before installing the replacement parts, inspect the new Final Drive Internal Gear/Parking Pawl Assembly to make sure it does not have a "dent".