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: 1988-92 M/L, G, C/K, R/V AND S/T VEHICLES

Some 1988-92 vehicles with HYDRA-MATIC 4L60/700R4 transmissions may exhibit a clicking or whining noise in third and fourth gear. A customer may also describe it as a ticking or rattle noise from the rear of the transmission. The clicking noise is caused by transmission fluid passing over the fric- tion 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).

SERVICE PROCEDURE

Install five new fiber plates in the low and reverse clutch. The new plates have a different groove configuration so they don't vibrate in third and fourth gear.

DATE OF PRODUCTION CHANGE

The new low and reverse fiber clutch plates were phased into production over several weeks as sufficient stock became available. Beginning February 20, 1992 (Julian Date 051) all HYDRA-MATIC 4L60 transmissions were built using the new fiber clutch plates.

SERVICE PARTS INFORMATION

Part Number Description ------ ----------- 8681813 Plate, Low and Reverse Clutch (Fiber)

Parts are available at GMSPO. In case of limited inventory, parts will be placed on 400 control to waive V.I.P. surcharges. Only verifiable emergency V.I.P. orders will be accepted. GMSPO will make every effort to obtain parts. However, the part will be shipped premium transportation at dealer's expense and all other order types will be placed on backorder until the 400 control is removed.

SERVICE MANUAL REFERENCE

Refer to the Automatic Transmission Unit Repair Section of the appropriate Service Manual for information on 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.