Chevrolet Silverado / GMC Sierra. Manual — part 2821

6. Repair small scratches or nicks with a soft stone.

7. Inspect the case threaded bolt holes for damage.

8. Repair any damaged threads.

9. Inspect the front output shaft rear bearing bore (2) for the following conditions:

Spun bearing

Cracks

10. Inspect the rear output shaft rear bearing bore (4) for the following conditions:

Spun bearing

Cracks

11. Replace the case if the bearing has spun. Refer to Transfer Case Disassemble and

Transfer Case Assemble.

12. Inspect the retaining ring (5) for the rear output shaft rear bearing for being bent or twisted.

13. Replace a faulty retaining ring.

14. Inspect the rear output shaft bushing (3) for scoring or wear.

15. Replace the case if the rear output shaft bushing is faulty. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

16. Replace the case if the control actuator lever shaft bore is faulty. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

Differential Components

2008 Chevrolet Silverado 1500

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

Silverado

Fig. 57: Inspecting Planetary Differential Components
Courtesy of GENERAL MOTORS CORP.

1. Clean the planetary differential in cleaning solvent. Do not disassemble the planetary

differential.

2. Air dry and ensure all cleaning solvent is removed from the bearings in the pinion gears (3).

Do not spin the pinion gears with compressed air.

3. Inspect the pinion gears for chipped teeth.

4. Inspect the pinion gears for debris embedded in the root of the teeth.

5. Inspect the pinion gears for excessive side movement from worn bushings or shafts.

2008 Chevrolet Silverado 1500

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

Silverado

6. Inspect the planetary housing for cracks at the web (1) of the housing.

7. Inspect the thrust washer surface (2) for scoring or excessive wear.

8. Inspect the planetary housing for distortion.

9. Inspect the planetary housing to mainshaft splines for excessive wear.

10. Replace the planetary differential if any of the above conditions are found.

11. Inspect the planetary thrust washers for excessive wear or scoring.

12. Replace the thrust washers if they are faulty.

Fig. 58: View Of Front & Rear Sun Gears
Courtesy of GENERAL MOTORS CORP.

13. Clean the front sun gear (1) and the rear sun gear (2) in cleaning solvent and air dry.

14. Inspect the teeth on the front sun gear (1) and the rear sun gear (2) for the following

conditions:

Chipped teeth

Excessively worn gear surfaces

2008 Chevrolet Silverado 1500

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

Silverado

Slight wear marks are normal.

Debris embedded in the root of the teeth

15. Inspect the thrust washer surfaces for excessive wear or scoring.

16. Replace the front sun gear (1) and the rear sun gear (2) if they are faulty.

Drive Chain and Sprockets

Fig. 59: Identifying Drive Chain, Drive Sprocket & Driven Sprocket
Courtesy of GENERAL MOTORS CORP.

1. Clean the drive chain (1), drive sprocket (2), and driven sprocket (3) in cleaning solvent and

air dry.

2008 Chevrolet Silverado 1500

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

Silverado