DRIVELINE SHUDDER/VIBRATION PROCEDURE INFORMATION

SOME 1982 "S" TRUCKS, LONG WHEEL BASE MODELS WITH TWO-PIECE PROPSHAFTS, BUILT PRIOR TO NOVEMBER 15, 1981 MAY EXHIBIT A SHUDDER OR VIBRATION DURING MEDIUM AND HEAVY ACCELERATION FROM APPROXIMATELY 5-20 MPH. TO MINIMIZE THIS CONDITION, AN INTERIM PRODUCTION CHANGE WAS INITIATED THAT ALIGNS THE FRONT AND REAR PROPSHAFT SLIP YOKES WITH EACH OTHER (FIGURE 1). THE DRIVELINE SHUDDER OR VIBRATION CAN BE SIGNIFICANTLY REDUCED BY REINDEXING THE REAR PROPSHAFT 90F FOLLOWING THE PROCEDURE NOTED BELOW: (1) REMOVE REAR PROSHAFT ASSEMBLY. (2) USING A SUITABLE GRINDING TOOL OR FILE, REMOVE THE WELD WHICH BRIDGES THE GAP BETWEEN TWO (2) OF THE MALE SPLINES OF THE FRONT PROPSHAFT ASSEMBLY. SEE FIGURE 1, LOCATION "A" AND FIGURE 2. (3) REINSTALL REAR PROPSHAFT ASSEMBLY BEING SURE TO CORRECTLY ALIGN THE SLIP YOKES AS ILLUSTRATED IN FIGURE 1. ILLUSTRATION

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.