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Chevrolet Silverado / GMC Sierra. Manual - part 2804
Fig. 2: Internal Components
Courtesy of GENERAL MOTORS CORP.
11
Rear Case Half
12
Front Output Shaft Seal
13
Vent
14
Input Shaft Seal
Callout
Component Name
1
Input Gear Bearing
2
Input Shaft
3
Drive Sprocket Bushing
4
Drive Sprocket
5
Drive Chain
6
Front Sun Gear
7
Planetary Differential Assembly
8
Rear Sun Gear Thrust Washer
9
Rear Sun Gear
10
Input Shaft Rear Support Bushing
11
Rear Output Shaft
12
Rear Output Shaft Bearing Outer Retaining Ring
13
Rear Output Shaft Bearing
14
Rear Output Shaft Bearing Retaining Ring
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
DIAGNOSTIC INFORMATION AND PROCEDURES
DIAGNOSTIC STARTING POINT - TRANSFER CASE
Begin the system diagnosis by reviewing the Symptoms - Transfer Case. The Symptoms -
Transfer Case will provide the following information:
The required visual/physical inspections
The list of symptoms
Use the Strategy Based Diagnosis in order to identify the correct procedure for diagnosing the
system.
SYMPTOMS - TRANSFER CASE
Strategy Based Diagnostics
Review the system operation in order to familiarize yourself with the system functions. Refer to
Transfer Case Description and Operation.
Visual/Physical Inspection
Inspect the easily accessible or visible system components for obvious damage, or for
conditions which could cause the symptom.
Inspect the transfer case for the proper fluid. Refer to Transfer Case Fluid Replacement.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:
Transfer Case Popping Noise
Transfer Case Whine or Rumble Noise
Transfer Case Growl or Grinding Noise
15
Front Output Shaft Rear Bearing
16
Driven Sprocket
17
Front Output Shaft Cup Plug
18
Front Output Shaft
19
Front Output Shaft Front Bearing
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
Transfer Case Shudder or Binding
Transfer Case Clunk during Acceleration and Deceleration
Transfer Case Leak Diagnosis
TRANSFER CASE POPPING NOISE
TRANSFER CASE WHINE OR RUMBLE NOISE
TRANSFER CASE GROWL OR GRINDING NOISE
Cause
Correction
DEFINITION: A faulty internal transfer case component that causes a popping noise in the
transfer case.
Review the Symptoms - Transfer Case and perform the necessary inspections.
Chain jump
Replace the chain and sprockets. Refer to Transfer Case
Disassemble and Transfer Case Assemble.
Replace the shaft bearings. Refer to Transfer Case
Disassemble and Transfer Case Assemble.
Inspect for damaged components caused by metal debris.
Refer to Transfer Case Disassemble and Transfer
Case Assemble.
Cause
Correction
DEFINITION: A faulty internal transfer case component that causes a whine noise in the
transfer case.
Review the Symptoms - Transfer Case and perform the necessary inspections.
Faulty bearings
1. Inspect all of the bearings and journals. Refer to
Transfer Case Cleaning and Inspection.
2. Replace any faulty bearings, and any components with
faulty bearing journals. Refer to Transfer Case
Disassemble and Transfer Case Assemble.
Cause
Correction
DEFINITION: A faulty internal transfer case component that causes a growl or grinding
noise in the transfer case while the vehicle is turning.
Review the Symptoms - Transfer Case and perform the necessary inspections.
Planetary differential
1. Inspect the planetary differential pinion gears for the
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
TRANSFER CASE SHUDDER OR BINDING
following conditions:
Chipped, bent or deformed teeth
Pinion gear bushings worn
Pinion gear thrust washers missing
Seized or binding pinion gears
Refer to Transfer Case Cleaning and
Inspection .
2. Inspect the planetary differential for deformation. Refer
to Transfer Case Cleaning and Inspection.
3. Replace the planetary differential assembly if faulty.
Refer to Transfer Case Disassemble and Transfer
Case Assemble.
Sun gears
1. Inspect the sun gears for the following conditions:
Gear tooth failure
Worn or galled thrust surfaces
Refer to Transfer Case Cleaning and
Inspection .
2. Replace the sun gears if faulty. Refer to Transfer Case
Disassemble and Transfer Case Assemble.
Thrust washer
1. Inspect the thrust washer for seizure to the planetary
differential.
2. Inspect the thrust washer for galling.
3. Replace the thrust washer if faulty and the mating
component if damaged. Refer to Transfer Case
Disassemble and Transfer Case Assemble.
Planetary differential not
timed properly
1. Inspect the planetary differential for being timed
properly. Refer to Transfer Case Assemble.
2. Properly time the planetary differential gears. Refer to
Transfer Case Assemble.
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &
Silverado
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