NO REVERSE/SLIPPING IN REVERSE REPEAT REVERSE BAND DISTRESS

SUBJECT: NO REVERSE, SLIPPING IN REVERSE AND/OR REPEAT REVERSE BAND DISTRESS (REPLACE TRANSAXLE CASE)

MODELS AFFECTED: ALL 1987-91 MODELS EQUIPPED WITH 4T60 (THM 440T4) TRANSAXLES

BULLETIN COVERS:

A vehicle equipped with a 1987-91 Hydra-Matic 4T60 transaxle may exhibit a condition of no reverse, slipping in reverse and/or repeat reverse band distress. This may be caused by an interference between the reverse band apply bracket and the case. The suspected transaxle cases have an additional wall thickness in the area where the reverse band apply pin engages the apply bracket. The band may never fully apply or release once caught and could cause premature band failure.

SERVICE PROCEDURE:

If the transaxle exhibits any of the symptoms discussed in this bulletin, inspect the case die number as shown in Figure 1 and the transaxle Julian Date. If the case die number matches the suspect numbers and the transaxle Julian Date is after the dates listed, disassemble the transaxle and check the case spline number (Figure 2) (located deep inside the barrel of the case next to the right axle seal). If it is listed below, replace the case. If the transaxle is not a suspect unit, then refer to the Automatic Transaxle Diagnosis section of the Service Manual for repair procedures.

DIE SPLINE JULIAN JULIAN NO. NO. DATE DATE DATE DATE --- --- ---- ---- ---- ---- 527 4543 July 25, 1988 207 to November 5, 1989 309 557 4542 March 19, 1990 078 to June 10, 1990 161 558 4541 January 29, 1990 029 to June 10, 1990 161 561 1524 July 15, 1987 156 to June 10, 1990 161 590 4542 March 6, 1989 065 to February 18, 1990 049 594 4544 January 15, 1990 015 to June 10, 1990 161

LABOR TIME INFORMATION:

Labor Operation: K7800 - Case, Transaxle - Replace Labor Time: See Chart Below

Vehicle Series

A C E H W 6.5 6.5 6.5 6.5 7.6

SERVICE PARTS INFORMATION:

Part Transaxle Number Description Model Year Model Usage ------ ----------- ---------- ----------- 8668986 Case, Transaxle 1990 OLAH

8662928 Case, Transaxle 1987-90 All with previous Park System built before September 25, 1989 (Julian Date 268)

Reference Buick Service Bulletin 90-7440-1 for more information on the new park lock system.

8668985 Case, Transaxle 1990-91 All except OLAH with new (common case for Park System built after new park system) September 24, 1989 (Julian Date 267)

Parts are now available from GMSPO.

SERVICE MANUAL REFERENCE:

Refer to the appropriate Service Manual for proper 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.