NEW BOTTOM PAN/CONTROLLED COMP PAN GASKET AND SERVICE INFO.

SUBJECT: NEW BOTTOM PAN AND CONTROLLED COMPRESSION BOTTOM PAN GASKET (SERVICE INFORMATION)

MODELS AFFECTED: 1984-92 CENTURY 1985-90 PARK AVENUE 1986-90 RIVIERA 1986-91 LESABRE 1988-90 REATTA 1988-92 REGAL

BULLETIN COVERS: (Figure 2) ------------------------------ A new transaxle Bottom Pan having a flat face along the pan rail and Controlled Compression Bottom Pan Gasket has been released for all Hydra-Matic 4T60 transaxles. The new pan must be used with the new gasket. This bottom pan and gasket assembly was designed to reduce the potential of bottom pan leaks. The new gasket is black in color and has a rubber-like texture. The controlled compression gasket is designed to be a REUSABLE GASKET.

DATE OF PRODUCTION CHANGE: (Figure 1) -------------------------------------- The controlled compression bottom pan gasket went into production on June 24, 1991 (Julian Date 175) for all Hydra-Matic 4T60 transaxles.

SERVICE PROCEDURE:

This new controlled compression bottom pan gasket can be used on all previous Hydra-Matic 4T60 transaxles when used with the new bottom pan and flanged hex head bolt. The old style conical washer screw can be used with the new bottom pan and controlled compression gasket, but the new flanged hex head bolt CANNOT be used on the old style bottom pan and gasket combination.

Bottom Pan Gasket Replacement:

1. Clean sealing surface of the bottom pan and machined surface of the transaxle case. If gasket is being reused, inspect the surface for damage and replace if needed. All mating surfaces must be clean and free of transaxle fluid.

2. Carefully align the bottom pan bolt holes with the gasket and transaxle case mounting holes. Install all bolts by hand and torque to 17 N.m (151 lb. in.).

Note: If the controlled compression gasket is being reused, clean the surface with a soft cloth. Use of solvents may cause damage to the gasket and affect its durability.

SERVICE PART INFORMATION:

Whenever ordering this new controlled compression gasket, refer to the following part numbers:

Service Part Number Description (Pkg Contents) Models ----------- -------------------------- ------ 8675995 Transaxle Bottom Pan Package All 4T60 (1) Pan, Transaxle Oil (1) Gasket, Transaxle Oil Pan (19) Bolt, Flanged Metric Hex Head (1) Magnet, Chip Collector

8678681 Transaxle Bottom Pan Gasket, Controlled Compression

Parts are currently available from GMSPO.

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.