A/T - Intermittent No Reverse or Locks In Reverse
87buick9Bulletin: 87-7440-10
Date: Sept., '87
Ref. No. 87-171-7440
Corp. Ref. No. 717105R
SUBJECT: INTERMITTENT NO REVERSE OR LOCKS IN REVERSE
MODELS AFFECTED: 1984-87 THM 440-T4 (ME9)
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".