Drivetrain - Front Axle Repair Precaution

GMC NUMBER: 92-4C-18

GROUP: 4C Front Axle

DATE: May, 1993

CORPORATE NUMBER: 164303R

SUBJECT:
REPLACING FRONT AXLE PARTS MAY RESULT IN VIBRATION (REPLACE ENTIRE AXLE ASSEMBLY)

MODELS:
1990-93 L-VAN

THIS BULLETIN CANCELS AND REPLACES GMC TRUCK BULLETIN 92-4C-18, DATED OCTOBER 1991. IT IS BEING REVISED TO INCLUDE THE 1993 MODEL YEAR.

Each front axle for 1990-1993 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 1990-1993 L-van front axle. If replacement of one of these parts is necessary, replace the entire axle assembly, using the system-balanced service axle assemblies listed below.

Prior to replacement of the 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 the pinion seal, the pinion yoke must be referenced to the pinion to ensure reassembly in the 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, reindex propeller shaft to transfer case and test drive again.

SERVICE PARTS INFORMATION:

Axle Part
Vehicle Ratio 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 Labor Time: 2.2 hrs.