PEDAL BUZZ AT ZERO TO LIGHT THROTTLE IN FORWARD GEAR

Subject: PEDAL BUZZ AT ZERO TO LIGHT THROTTLE IN FORWARD GEAR RANGES (NEW SPACER PLATE)

Models Affected: 1990-91 SUNBIRD W/3.lL, GRAND AM AND GRAND PRIX W/2.3L, 3T40

This bulletin has been revised to include serial number information stated under section "DATE OF PRODUCTION CHANGE". Part numbers have been updated. This bulletin cancels and replaces bulletin 91-7-9 issued 9190.

BULLETIN COVERS:

A new Spacer Plate (20) with a smaller 1-2 accumulator orifice which will reduce the potential for pedal buzz. This pedal buzz is noticeable at zero to light throttle in forward gear ranges caused by unstable operation of the 1-2 accumulator valve.

DATE OF PRODUCTION CHANGE:

This new spacer plate went into production in all "K" and "L" model HYDRA-MATIC 3T40 transaxles for the 1991 model year on July 30, 1990 (Julian Date 211).

NOTE: 1991 KKC model transaxles with serial numbers built between 1011 - 1830 and built after July 30, 1990 (Julian Date 211) are affected.

SERVICE PROCEDURE:

To service any HYDRA-MATIC 3T40 for a pedal buzz condition, replace the (existing) spacer plate with a new spacer plate which contains the smaller 1-2 accumulator orifice.

SERVICE PARTS INFORMATION:

Refer to the following part numbers whenever ordering this new spacer plate.

Package Description Part Number and Transaxle Model ------------------- ------------------------------- Spacer Plate 8678035 - KDC " " 8678489 - KKC " " 8678488 - KNC " " 8678038 - KXC (1991 Only) " " 8678163 - LJC " " 8678164 - LKC " " " " - LLC

Parts are currently available from GMSPO.

SERVICE MANUAL REFERENCE:

Whenever service to the Spacer Plate or valve body assembly is necessary, refer to the HYDRA-MATIC 3T40 Unit Repair Section of your service manual.

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.