For 1990-2009 cars

# PINION BEARING NOISE PRE-LOAD & SPECIFICATION

A PINION BEARING NOISE MAY OCCUR ON 1982 'F' SERIES VEHICLES AS A RESULT OF CASE DISTORTION AT THE FRONT PINION BEARING OUTER RACE LOCATION. THE DISTORTION CAN OCCUR AS A RESULT OF HIGH BOLT TORQUE ON THE TORQUE ARM TO CASE ATTACHING BOLTS. THIS CASE DISTORTION CAN INCREASE THE BEARING PRELOAD BEYOND ITS LIMITS AND CAUSE SPALLING OF THE BEARING. IF A DIFFERENTIAL TEARDOWN IS REQUIRED AS A RESULT OF THE ABOVE CONDITIONS, A CHANGE IN PROCEDURE SHOULD BE USED DURING THE REASSEMBLY OPERATION. A.REPLACE BOTH FRONT AND REAR PINION BEARINGS BEING SURE SHIM SELECTION IS CORRECT. PINION BEARING PRELOAD SHOULD BE SET TO THE MINIMUM SPECIFIED TORQUE OF 2.7 N.M (24 IN. LB.) WITH THE TORQUE ARM TO CASE BOLTS LOOSE. B.ROTATE THE PINION SEVERAL TIMES AND RECHECK THE PRELOAD TO ASSURE IT HAS MAINTAINED THE INITIAL SETTING. TIGHTEN TORQUE ARM TO CASE BOLTS TO MINIMUM SPECIFIED TORQUE OF 115 N.M (85 FT. LB.). IN THOSE INSTANCES WHERE PINION BEARINGS, RING AND PINION GEAR SETS, OR AXLE HOUSINGS ARE REPLACED OR ADJUSTED, THE PRE-LOAD MUST BE SET AT THE MINIMUM SPECIFICATION AS OUTLINED ON PAGE 15 IN SECTION 4-B OF THE FIREBIRD OR CAMARO SERVICE MANUALS. ALSO, WHEN RECONNECTING THE TORQUE ARM TO THE AXLE HOUSING, THE THROUGH BOLTS MUST BE TORQUED TO THE MINIMUM FACTORY SPECIFICATION, 115 N.M (85 FT. LB.). THESE SPECIFICATIONS MUST BE MAINTAINED TO AVOID EXCESSIVE LOADS ON THE PINION BEARING.

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.