Some owners of 1988-92 C/K, RN trucks and G vans 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.
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.
Refer to the appropriate service manual Section 4B REAR AXLE, "PINION FLANGE, DUST DEFLECTOR/OIL SEAL REPLACEMENT" for replacement procedure.
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.
Part Number Description Qty/Veh. ------ ----------- -------- 26033578 Seal, Differential Pinion 1
Parts are available. In case of limited inventory, parts will be placed on 400 control to waive VIP surcharges. Only verifiable emergency orders will be accepted. GMSPO will make every effort to obtain parts. However, the part will be shipped premium transportation at the dealer's expense and all other order types will be placed on backorder until the 400 control is removed.
For vehicles repaired under warranty use:
Labor Operation: F2023
Labor Time: Refer to appropriate Labor Time Guide for Labor 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.