Drivetrain - Front Axle Growl Noise in 2wd Only

90chevy15
GMC NUMBER: 89-4C-133

GROUP: 4C Front Axle

DATE: June, 1990

CORPORATE
NUMBER: 064301
SUBJECT: FRONT DIFFERENTIAL GROWL NOISE

MODELS: 1988-89 K1, K2 TRUCKS
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.

Figure No. 1:

Repair Procedure:
Replace the front axle side gears as shown in section 4C of the applicable model year unit repair manual. 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, pin-
ion 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.