CLICK/WHINE IN 3RD/4TH GEAR INST. NEW CLUTCH FIBER PLATES

Subject: CLICK/WHINE IN THIRD/FOURTH GEAR (INSTALL NEW LOW AND REVERSE CLUTCH FIBER PLATES)

Models Affected: 1988-93 FIREBIRD WITH 4L60 (MD8) 1988-89 SAFARI WAGON 700R4 (M08)

THIS BULLETIN IS BEING REVISED TO ADD THE 1993 MODEL YEAR, ADD THE "NOTE" IN CORRECTION SECTION AND CHANGE THE SERVICE PARTS INFORMATION. THIS BULLETIN CANCELS AND REPLACES BULLETIN 92-7-14 ISSUED 4/92.

CONDITION:

--------- Some 1988-93 vehicles with HYDRA-MATIC 4L60 transmissions built before November 19, 1992 (Julian Date 324) may exhibit a clicking or whining noise in third and fourth gear. A customer may also describe it as a ticking or rattle noise.

CAUSE:

----- The clicking noise is caused by transmission fluid passing over the friction plates of the low and reverse clutch. The fluid causes them to vibrate when the low and reverse clutch is not applied (third and fourth gear).

CORRECTION:

---------- Install five new fiber plates in the low and reverse clutch. The new plates have a non-groove configuration.

NOTE: All HYDRA-MATIC 4L60 transmissions built on or after November 19, 1992 (Julian Date 324) have been assembled with the new low and reverse clutch fiber plates.

SERVICE PARTS INFORMATION:

DESCRIPTION PART NUMBER TRANSMISSION ----------- ------------ ------------ Plate Asm.,-Low and Reverse Clutch 8684089 4L60

Parts are expected to be available on 6/07/93.

Refer to the Automatic Transmission Unit Repair Section of the appropriate Service Manual for information in replacing the low and reverse clutch friction plates.

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.