Drivetrain - Front Axle Growl
90chevy27Number: 89-312-4A
Section: 4A
Date: June 1990
Corp. Bulletin No.: 064301
Subject: FRONT DIFFERENTIAL GROWL NOISE
Model and Year: 1988-89 K1, K2 TRUCKS
TO: ALL CHEVROLET DEALERS
Front axle growl noise due to improperly machined side and differential gears may be evident in some 1988-89 K1 and K2 vehicles. Affected vehicles can be repaired by replacing the front axle side and differential gears only when all of the following criteria are true.
1. Growl noise happens in two wheel drive only. Subject noise will not be evident when the truck is in four wheel drive.
2. The noise is intermittent - the growl will not always be present under the same conditions.
3. Putting pressure (pulling back) on the transfer case shift lever causes the noise to go away.
If all of these conditions are not present, do not attempt this repair procedure as it will not yield the desired result.
Repair Procedure:
Replace the front axle side gears as shown in section 4C of the applicable model year unit repair manual.
Figure No. 1:
Refer to Figure 1.
IMPORTANT: The new front differential gear service kit has non-identical side gears. The bell end has a ring, output shaft connector (snap ring) and the flange end has a straight spline with no snap ring.
SERVICE PARTS INFORMATION
Part Number Description
26022410 Gear Service Kit (2 side gear assemblies, 4
thrust washers, pinion shaft, and
pinion shaft lock pin)
Parts are currently available through GMSPO.
WARRANTY INFORMATION
For vehicles repaired under warranty use:
Labor Operation: F2122
Labor Time: 2.8 hrs.