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Chevrolet Silverado / GMC Sierra. Manual - part 1319
11
Carrier Housing
12
Output Shaft Seal Assembly
13
Output Shaft
14
Drain Plug Assembly
15
Drain Plug Washer
16
Fill Plug Assembly
17
Fill Plug O-ring Seal
18
Carrier Locator Pin
19
Vent Connector
20
Differential Case
21
Ring Gear
22
Output Shaft Bearing Assembly
23
8-Point Lock Ring
24
Sleeve and Insert Assembly
25
Differential Side Bearing Assembly
26
Differential Cross Pin Lock
27
Differential Pinion Thrust Washer
28
Differential Pinion Gear
29
Differential Side Gear Washer
30
Differential Side Gear
31
Output Shaft Snap Ring
32
Differential Pinion Gear
33
Differential Pinion Gear Thrust Washer
34
Differential Side Gear
35
Differential Side Gear Washer
36
Differential Cross Pin
37
Ring Gear Bolt
38
Output Shaft Bearing Assembly
39
8-Point Lock Ring
40
Sleeve and Insert Assembly
41
Differential Side Bearing Assembly
42
Carrier Gasket
43
Carrier Cover
44
Tube Locator Pin
45
Inner Output Shaft Thrust Washer
46
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Front Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
DIAGNOSTIC INFORMATION AND PROCEDURES
DIAGNOSTIC STARTING POINT - FRONT DRIVE AXLE
Begin the system diagnosis by reviewing the system Description and Operation. Refer to Front
Drive Axle Description and Operation. Reviewing the Description and Operation information
will help you determine the correct symptom diagnostic procedure when a malfunction exist.
Reviewing the Description and Operation information will also help you determine if the
condition described by the customer is normal operation. Refer to Symptoms - Front Drive
Axle in order to identify the correct procedure for diagnosing the system and where the
procedure is located.
SYMPTOMS - FRONT DRIVE AXLE
Before beginning diagnosis, review the system description and operation in order to familiarize
yourself with the system functions. Refer to Front Drive Axle Description and Operation.
Noise Diagnosis
Any gear-driven unit produces a certain amount of noise that is normal and that conventional
repairs or adjustment cannot eliminate. Slight noise that is heard only at a certain speed or under
unusual or remote conditions is acceptable. For example, this noise tends to reach a peak at
Inner Output Shaft Bearing Assembly
47
Inner Output Shaft
48
Carrier Bolt
49
Shifter Spring
50
Shifter Fork
51
Shifter Fork Rod
52
Tube Bolt
53
Shift Actuator Assembly
54
Output Shaft Seal Assembly
55
Output Shaft Bearing Assembly
56
Tube
57
Tube Gasket
58
Output Shaft Locator Thrust Washer
59
Output Shaft Thrust Washer
60
Output Shaft Snap Ring
61
Shifter Sleeve
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Front Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
speeds from 60-100 km/h (40-60 mph) depending upon road and load conditions, or upon gear
ratio and tire size. Noise of this kind does not indicate trouble in the axle assembly.
When an axle is suspected of being noisy, make a thorough test in order to determine whether the
noise originates in the tires, road surface, wheel bearings, engine, transmission, propeller shaft, or
axle assembly.
Classifying the Symptom
Front Drive Axle symptoms can usually be classified into the following categories:
Leaks
Noises
Vibrations
Leak and noise related symptoms are diagnosed within the Front Drive Axle section. For
vibration related symptoms, refer to Diagnostic Starting Point - Vibration Diagnosis and
Correction .
Visual/Physical Inspection
Inspect the system for loose or missing fasteners.
Inspect the system for loose or leaking components.
Inspect the system for obvious damage or conditions which may cause the symptom.
Symptoms List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom.
Front Drive Axle Noises
Noisy in Drive
Noisy When Coasting
Intermittent Noise
Constant Noise
Noisy on Turns
Front Axle Lubricant Leak Diagnosis
FRONT DRIVE AXLE NOISES
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Front Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Gear Noise
Gear noise or whine is audible from 32-89 km/h (20-55 mph) under 4 driving conditions:
Drive-Acceleration or heavy pull
Road Load-Vehicle driving load or constant speed
Float-Using enough throttle to keep the vehicle from driving the engine, the vehicle slows
down gradually but the engine still pulls slightly.
Coast-Throttle is closed and the vehicle is in gear.
Gear noise most frequently has periods where the noise is more prominent, usually between 48-64
km/h (30-40 mph) and 80-85 km/h (50-53 mph). Gear whine is corrected by ring and pinion gear
replacement or adjustment, depending on the mileage of the gear set.
Bearing Noise
Faulty bearings produce a rough growl or grating sound, rather than the whine typical of gear
noise. Bearing noise (hum) will pulsate at a constant vehicle speed. This indicates a bad pinion or
a bad front axle side bearing. This noise can be confused with front wheel bearing noise. Inspect
and replace the bearings and the affected components as required.
Front Wheel Bearing Noise
A rough front wheel bearing produces a noise which continues with the vehicle coasting at low
speed and the transmission in neutral. The noise may diminish some when the brakes are gently
applied. The noise may also change when performing side-to-side maneuvers with the vehicle.
A rough and/or noisy wheel bearing can be heard by spinning the wheels by hand and listening at
the hubs for the noise. Inspect and replace the bearings and the affected components as needed.
Knock at Low Speeds
A low speed knock can be caused by a differential case side gear bore that has worn oversize.
Inspect the side gears and the differential case assembly and replace the components as necessary.
Backlash Clunk
Excessive backlash clunk under acceleration or de-acceleration can be caused by any of the
following:
Worn differential pinion shaft
Worn differential pinion and/or side gear teeth
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Front Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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