DRIVELINE RATTLE AT 40 MPH WITH TCC ENGAGED

Model and Year: 1988-90 K1, K2 TRUCKS AND 1989-90 V1, V2 TRUCKS WITH 700-R4 4L60 AUTOMATIC TRANSMISSION AND 5.0L (VIN CODE H) OR 5.7L (VIN CODE K) ENGINES

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 90-100-4A, DATED NOVEMBER 1989. THE TORQUE CONVERTER PART NUMBER HAS BEEN CHANGED, AS WELL AS A TRUCK SERIES ADDED AND NEW LABOR INFORMATION ADDED. ALL COPIES OF 90-100-4A SHOULD BE DISCARDED.

Driveline rattle at 40 MPH with TCC engaged can be eliminated in V and K model vehicles with 5.0L or 5.7L gas engines and 700R4 automatic transmissions by installing a new torque converter, part number 8650935. The new torque converter has an increased compression converter clutch spring and will eliminate the vibration which is sometimes heard as driveline rattle.

PARTS INFORMATION:

Part Number Description

8650935 torque converter

Parts are currently available through GMSPO.

WARRANTY INFORMATION:

For vehicles repaired under warranty use:

LABOR OPERATION: T8145*

LABOR TIME: K models 4.0 hrs. V models 3.4 hrs.

ADD: With skid plate 0.2 hr.

* Labor operation is coded to base vehicle coverage in the warranty system.

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.