Drivetrain - Front Axle R&R Precaution/Vibration

91chevy23

Number: 92-23-4C

Section: 4C

Date: OCT. 1991

Corporate Bulletin No.: 164303R

ASE No.: A3


Subject: REPLACING FRONT AXLE PARTS MAY RESULT IN VIBRATION


Model and Year: 1990-92 L VAN


THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN N0. 91-393-4C, DATED AUGUST 1991. THE 1992 MODEL YEAR HAS BEEN ADDED AND THE WORDS "PINION OIL SEAL" DELETED FROM THE SECOND PARAGRAPH. ALL COPIES OF 91-393-4C SHOULD BE DISCARDED.

Each front axle for 1990-1991 L Vans is balanced with the pinion flange assembly modified to act as a harmonic member which reduces audible driveline disturbance.

Replacing the ring and pinion gear set, pinion flange assembly, or the pinion bearings may disturb the balance integrity of the axle and result in vibration.

Do not replace either the ring and pinion gear set, pinion flange assembly, or the pinion bearings in a 1990-1991 L Van front axle. If replacement of one of these parts is necessary, replace the axle assembly using the system balanced service axle assemblies listed below.

Prior to replacement of axle assembly, it is essential that the position of the propeller shaft relative to all of the driveline components be observed and reference marked. When replacing pinion seal, pinion yoke must be referenced to pinion, to assure re-assembly in original position. All components must be reassembled in the same relationship to each other. Attach propeller shaft to replacement axle first, then to the transfer case, and road test. If vibration is noted, then reindex propeller shaft to transfer case and test drive again.

SERVICE PARTS INFORMATION:

Vehicle Axle Ratio Part Number Description

L Van 3.42 26022779 Service Axle Assembly
L Van 3.73 26022781 Service Axle Assembly

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

For vehicles repaired under warranty use:

Labor Operation: F2142

Use applicable labor time guide for labor hours.