G 3500 1 Ton Van V8-379 6.2L DSL VIN J FI (1992)
Differential Clutch: Customer Interest
Locking Rear Axle - Chatters onTurns
GMC NUMBER:
91-4B-124
GROUP:
4B Rear Axle
DATE:
July, 1991
CORPORATE
NUMBER:
964201R
SUBJECT:
LOCKING REAR AXLE CHATTER
MODELS:
ALL LIGHT DUTY TRUCKS EQUIPPED WITH LOCKING REAR AXLES, RPO G80
THIS BULLETIN CANCELS AND REPLACES GMC TRUCK SERVICE BULLETIN 90-4B-30 (CORPORATE NUMBER 964201) DATED
JANUARY, 1990 TO ADD WARRANTY INFORMATION. ALL COPIES OF 90-4B-30 SHOULD BE DISCARDED.
Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.
This condition of alternate engagement and disengagement of the clutches in the differential assembly is usually caused by contaminated axle lubricant.
To correct this condition, drain and refill the rear axle with SAE 80W-90 GL5 (P/N 1052271). The use of any additive in locking rear axles (G80) is not
recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped
with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle
life.
VEHICLES/COMPONENTS INVOLVED:
Some light duty trucks equipped with locking rear axles, RPO G80.
SERVICE PARTS INFORMATION:
Part Number
Description
1052271
Lubricant, Rear Axle (24 oz.)
See Appropriate
Gasket, Rear Axle Housing
Parts Manual
Cover
Parts are currently available through GMSPO.
WARRANTY INFORMATION:
As specified in Light Duty Truck Maintenance Schedules, locking rear axle fluid drain and refill is required owner maintenance at the first engine oil
change. Failure to drain and refill the rear axle as specified may contribute to a later axle chatter condition. Refer to the appropriate Light Duty Truck
Maintenance Schedule or service manual, section OB, for further details on change intervals. For those vehicles repaired under warranty, which have had
the axle fluid changed at the first oil change and have experienced rear axle chatter use:
Labor Operation:
F2010, Locking Differential - Flush
Labor Time:
0.9 hr. (All Models)