Hummer H2. Manual - part 2658

SERVICE INDICATOR ALWAYS ON

Circuit Description

The Service 4WD indicator is located in the instrument panel cluster (IPC), and shares the common power and
ground of the IPC. The transfer case shift control module controls the Service indicator by sending the IPC a
Class 2 message. This indicator may be controlled with the scan tool using the IPC device controls.

Test Description

The number below refers to the step number on the diagnostic table.

2: This step determines whether the failure is the result of a malfunctioning transfer case shift control
module or the IPC.

Service Indicator Always On

SERVICE INDICATOR INOPERATIVE

Circuit Description

The Service 4WD indicator is located in the instrument panel cluster (IPC), and shares the common power and
ground of the IPC. The transfer case shift control module controls the Service indicator lamp by sending the
IPC a Class 2 message. This lamp may be controlled with the scan tool using the IPC device controls.

Test Description

Step

Action

Yes

Schematic Reference: Transfer Case Control Schematics
Connector End View Reference: Transfer Case Control Connector End Views

Did you perform the Diagnostic System Check - Transfer
Case?

Go to

Step 2

Go to Diagnostic System

Check - Transfer Case

In the IPC Data List, observe the Service 4WD input/output.
Is the Service 4WD indicator commanded ON?

Go to

Step 3

Go to Step 4

Replace the transfer case shift control module. Refer to
Transfer Case Shift Control Module Replacement .
Did you complete the repair?

Go to

Step 5

Replace the instrument panel cluster. Refer to Instrument
Panel Cluster (IPC) Replacement in Instrument Panel,
Gauges, and Console.
Did you complete the repair?

Go to

Step 5

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle in order to determine if the symptom

has been corrected.

Is the symptom still present?

Go to

Step 1

System OK

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

The number below refers to the step number on the diagnostic table.

2: This step determines whether the failure is the result of a faulty transfer case shift control module or
the IPC.

Service Indicator Inoperative

TRANSFER CASE POPPING NOISE

Transfer Case Popping Noise

TRANSFER CASE WHINE OR RUMBLE NOISE

Transfer Case Whine or Rumble Noise

Step

Action

Yes

Schematic Reference: Transfer Case Control Schematics
Connector End View Reference: Transfer Case Control Connector End Views

Did you perform the Diagnostic System Check - Transfer
Case?

Go to

Step 2

Go to Diagnostic System

Check - Transfer Case

In the IPC Data List, observe the Service 4WD input/output.
Is the Service 4WD indicator commanded ON?

Go to

Step 4

Go to Step 3

Replace the transfer case shift control module. Refer to
Transfer Case Shift Control Module Replacement .
Did you complete the repair?

Go to

Step 5

Replace the instrument panel cluster. Refer to Instrument
Panel Cluster (IPC) Replacement in Instrument Panel,
Gauges, and Console.
Did you complete the repair?

Go to

Step 5

1. Use the scan tool in order to clear the DTCs.

2. Operate the vehicle in order to determine if the symptom

has been corrected.

Is the symptom still present?

Go to

Step 1

System OK

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

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

TRANSFER CASE GROWL OR GRINDING NOISE

Transfer Case Growl or Grinding Noise

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 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.
High/low planetary
carrier assembly

1. Inspect the high/low planetary carrier pinion gears for the following

conditions:

Chipped, bent or deformed teeth

Pinion gear needle bearing worn

Pinion gear thrust washers missing

Seized or binding pinion gears

Refer to Cleaning and Inspection .

2. Inspect the high/low planetary carrier input gear for excessive thrust end

play.

3. Inspect the input gear teeth for excessive wear or damage.

4. Replace the high/low planetary carrier assembly if any of the above

conditions exist. Refer to Transfer Case Disassemble and Transfer Case
Assemble .

Annulus gear

1. Inspect the annulus gear for teeth damage or wear. Refer to Cleaning and

Inspection .

2. Replace the annulus gear if it is faulty. Refer to Transfer Case

Disassemble and Transfer Case Assemble .

Planetary differential

1. Inspect the planetary differential pinion gears for the following conditions:

Chipped, bent or deformed teeth

Pinion gear bushings worn

Pinion gear thrust washers missing

Seized or binding pinion gears

Refer to Cleaning and Inspection .

2. Inspect the planetary differential for deformation. Refer to Cleaning and

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

TRANSFER CASE CLUNK IN 4HI LOCK

Transfer Case Clunk in 4HI Lock

Inspection .

3. Replace the planetary differential assembly if it is 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 Cleaning and Inspection .

2. Replace the sun gears if they are faulty. Refer to Transfer Case

Disassemble and Transfer Case Assemble .

Thrust washers

1. Inspect the thrust washers for seizure to the planetary differential.

2. Inspect the thrust washers for galling.

3. Replace the thrust washers if they are faulty and the mating component if

it is 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 .

Cause

Correction

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in
the 4HI Lock range only.
Review the Symptoms - Transfer Case and perform the necessary inspections.
Incorrect fluid level or
incorrect fluid

1. Inspect the transfer case for the correct fluid level. Refer to Transfer

Case Fluid Replacement .

2. Inspect the transfer case for the correct type of fluid.

3. Flush the transfer case and fill with the correct fluid, if required.

Refer to Capacities - Approximate Fluid .

Worn high speed teeth on
the range sleeve

1. Inspect for worn high speed teeth on the range sleeve. Refer to

Cleaning and Inspection .

2. Replace the range sleeve if it is faulty. Refer to Transfer Case

Disassemble and Transfer Case Assemble .

Worn or missing input gear
thrust washer

Replace the worn or missing input gear thrust washer. Refer to Transfer
Case Disassemble and Transfer Case Assemble .

Worn or faulty planetary
differential

1. Inspect the planetary differential for the following conditions:

Loose planetary differential splines to mainshaft splines

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

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