LOCKING DIFFERENTIAL (G80) LUBRICANT SERVICE INFORMATION

VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS

GMC does not recommend the use of any limited slip additives in light trucks with G80 axles. Rear axle additives delay the engagement of the locking mechanism and may decrease axle life.

The recommended lubricant for all light truck rear axles, including G80, is SAE 80W-90 GL5 (GM part #10950849). Trucks exhibiting rear axle chatter should be drained and refilled using the rear axle fluid indicated.

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.