A/T - Click/Whine In Third/Fourth Gear

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GMC NUMBER: 92-7A-75

GROUP: 7A Automatic Transmission

DATE: April 1992

CORPORATE
NUMBER: 277121


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 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).

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 to the appropriate Service Manual for information on replacing the low and reverse clutch friction plates.