For 1990-2009 cars

# REAR AXLE PINION SEAL LEAK (INSTALL NEW SEAL)

#### SUBJECT: REAR AXLE PINION SEAL LEAK (INSTALL NEW SEAL)

#### VEHICLES AFFECTED: 1988-92 C/K, R/V AND G TRUCKS AND D CAR

This bulletin is being revised to add the Cadillac D car, another cause and to add more information about the part.

Some owners of 1988-92 C/K, R/V, and G trucks and D cars equipped with 8-1/2 inch ring gear rear axles may comment that their vehicle experiences a leak at the rear axle pinion seal.

Leaks may be the result of dirt entering the seal causing increased wear of the sealing material or by the seal losing elasticity after repeated exposure to high temperatures.

This leak may be corrected by installing a new seal which features a double lip design. The previous pinion seal was a single lip design. This seal is more resistant to dirt intrusion and loss of elasticity.

#### SERVICE PROCEDURE:

Refer to the appropriate service manual Section 4B REAR AXLE, "PINION FLANGE, DUST DEFLECTOR/OIL SEAL REPLACEMENT" for replacement procedure.

#### IMPORTANT: Reassembly of the pinion flange in the same location is important to avoid vibration. Be certain to scribe a line on the pinion stem, pinion nut and pinion flange and record the number of exposed threads on the pinion stem as described in the service manual. This is especially important on 1992 C/K Utilities and Suburbans and G-Vans as these axles are system balanced as a unit with the pinion flange weighted as a harmonic member.

#### SERVICE PARTS INFORMATION:

Part Number Description Qty/Veh ----------- ----------- ------- 26033578 Seal, Differential Pinion 1

For vehicles repaired under warranty use:

Refer to appropriate Labour Time Guide for Labour Operation and Labour Time.

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.