Chevrolet Silverado / GMC Sierra. Service manual — part 2806

2. Install the plugs correctly. Refer to Transfer Case Fluid

Replacement.

Rear output shaft seal
leaking

1. Inspect for the following conditions:

Overfilled or improper transfer case fluid

Blocked vent

Seal improperly installed, worn, or damaged

Seal bore damaged or cracked

Rear output shaft bushing for excessive wear

Slip yoke seal surface for wear or pitting

2. Repair or replace the following components if found

faulty:

Adjust or replace the transfer case fluid. Refer to
Transfer Case Fluid Replacement .

Clean, or properly route the vent hose.

Replace the slip yoke if the surface could cause
leakage. Refer to One-Piece Propeller Shaft
Replacement or Two-Piece Propeller Shaft
Replacement .

Replace the rear case half if the bushing is worn.
Refer to Transfer Case Disassemble and
Transfer Case Assemble .

Replace the rear case half if the seal bore is
damaged. Refer to Transfer Case Disassemble
and Transfer Case Assemble .

Replace the rear output shaft seal. Refer to Rear
Output Shaft Seal Replacement .

Front output shaft seal
leaking

1. Inspect for the following conditions:

Overfilled or improper transfer case fluid

Blocked vent

Seal improperly installed, worn, or damaged

Seal bore damaged or cracked

2. Repair or replace the following components if found

faulty:

Adjust or replace the transfer case fluid. Refer to

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Transfer Case Fluid Replacement .

Clean or properly route the vent hose.

Replace the front case half if the seal bore is
damaged. Refer to Transfer Case Disassemble
and Transfer Case Assemble .

Replace the front output shaft seal. Refer to Front
Output Shaft Seal Replacement .

Leaking at the vent

Transfer case overfilled

1. Inspect for the correct transfer case fluid level.

Refer to Transfer Case Fluid Replacement .

2. Inspect the transmission fluid level. Refer to

Transmission Fluid Check .

3. If the transmission fluid level is low, and the

transfer case fluid level is too high, replace the
transfer case input shaft seal. Refer to Input Shaft
Seal Replacement .

4. Inspect for the following conditions:

Seal improperly installed, worn, or damaged

Seal bore damaged or cracked

Input shaft seal surface worn, grooved, or
damaged

Seal the vent with the correct sealer if leaking at the case.
Refer to Transfer Case Assemble.

Transfer case to adapter
leak

1. Inspect for the following conditions:

Loose mounting fasteners

Gasket or sealant faulty

The transfer case input shaft seal leaking

2. Repair or replace the following components if found

faulty:

Replace the transfer case input shaft seal. Refer to
Input Shaft Seal Replacement .

Inspect for the following:

Seal improperly installed, worn, or damaged

Seal bore damaged or cracked

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

REPAIR INSTRUCTIONS - ON VEHICLE

TRANSFER CASE SHIELD REPLACEMENT

Fig. 3: View Of Transfer Case Shields & Bolts
Courtesy of GENERAL MOTORS CORP.

Input shaft seal surface worn, grooved, or
damaged

Repair or replace the loose fasteners. Refer to
Transfer Case Adapter Replacement .

Replace the transfer case gasket or sealer. Refer to
Transfer Case Adapter Replacement .

Front case half to rear case
half seam leak

Disassemble and seal the case halves. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

Case leaking

1. Inspect for a cracked case or case porosity.

2. Replace the faulty case half. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

TRANSFER CASE FLUID REPLACEMENT

Removal Procedure

Callout

Component Name

Preliminary Procedure:
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

1

Transfer Case Shield Bolt

Tighten: 20 N.m (15 lb ft)

NOTE:

Refer to Fastener Notice .

2

Transfer Case Shield

IMPORTANT: When performing the following procedure, use only hand tools to

remove and install the drain and fill plugs.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado