Yukon/Denali 4WD V8-4.8L VIN V (2005)
Differential Case: All Technical Service Bulletins
Drivetrain - Growl/Moan Noise From Front Axle
Bulletin No.: 03-04-19-004B
Date: December 12, 2005
TECHNICAL
Subject:
Growl or Moan Noise Coming From Front Axle (Replace Front Axle Differential Case)
Models:
2003-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003-2006 GMC Sierra, Yukon, Yukon XL
with 4WD and Active Transfer Case (RPO NP8) and 8.25 Inch Front Axle
Supercede:
This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 03-04-19-004A (Section 04 - Driveline/Axle).
Condition
Some customers may comment on a growl or moan-type noise coming from the front axle above 50 km/h (30 mph). This condition may be described as a
noise that phases or cycles in and out. This noise is present in the 2WD mode only, and may be present whether the vehicle is accelerating, decelerating,
or at a steady speed. The noise goes away in 4WD or Auto 4WD modes.
Cause
This noise may be caused by a low clearance condition within the differential in the front axle assembly. In the 2WD mode, the front differential has a
large amount of relative motion between the differential pinion and side gears. In the 4WD or Auto 4WD modes, the transfer case motors the front
propeller shaft, and the relative motion between the differential gears is reduced or eliminated, so the noise is eliminated.
Correction
Replace the front differential case, P/N 26018131. This is the component bolted to the ring gear. It is NOT necessary to replace the differential gears
unless unusual wear is observed. Use the procedure listed below.
1.
Raise the vehicle.
2.
Remove the front engine protection shield. Refer to Engine Protection Shield Replacement in the Frame and Underbody sub-section of the Service
Manual.
3.
Drain the differential carrier assembly.
4.
Disconnect the electrical connector from the actuator and wire harness from the right inner axle shaft housing and differential carrier.
5.
Remove the right wheel driveshaft inboard flange bolts from the inner axle shaft.
6.
Disconnect the right wheel driveshaft from the inner axle shaft.
7.
Remove the inner axle shaft housing nuts from the bracket.
8.
Remove the inner axle shaft housing bolts from the differential carrier assembly.
9.
Carefully remove the inner axle shaft housing assembly from the differential carrier.
10.
Remove the left wheel driveshaft inboard flange bolts from the inner axle shaft.
11.
Remove the left inner axle shaft from the differential carrier assembly.
12.
Remove the front drive axle clutch shaft from the differential carrier assembly.
13.
Remove the differential carrier assembly bolts.
