Rear Axle Replacement 15/25Series

1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Place jack or utility stands (such as GMDE 123-B67313) at the front end of the vehicle.
3. Drain the axle lubricant from the rear axle. Refer to Lubricant Change .
4. Disconnect the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement .
5. Remove the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
6. Disconnect the parking brake cable. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side in Park Brake.
7. Remove the brake line bracket bolts. Suspend the brake lines from the vehicle with heavy mechanics wire.
8. Remove the brake calipers from the brake caliper mounting brackets. Do not disconnect the brake lines. Suspend the calipers from the vehicle with heavy mechanics wire. Refer to Rear Brake Caliper Replacement in Disc Brakes.
9. Disconnect the shock absorbers from the axle brackets. Refer to Shock Absorber Replacement in Rear Suspension.
10. Remove the vent hose from the rear axle vent fitting. Refer to Vent Hose Replacement .
11. Remove the nuts and the washers from the U-bolts.
12. Remove the U-bolts, the spring plates and the spacers form the axle assembly.
13. Lower the axle assembly.

1. Place the rear axle assembly under the vehicle.
2. Align the rear axle assembly with the springs.
3. Connect the spacers, the spring plates and the U-bolts to the rear axle.
4. Raise the rear axle assembly into position.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

5. Install the washers if equipped and the nuts to the U-bolts.

Tighten

•	15 Series tighten the nuts in a criss cross pattern to 72 N·m (53 lb ft).

•	25 series tighten the nuts in a criss cross pattern to 150 N·m (110 lb ft).

6. Install the vent hose to the rear axle vent fitting. Refer to Vent Hose Replacement .
7. Connect the shock absorbers to the rear axle. Refer to Shock Absorber Replacement in Rear Suspension.
8. Install the brake calipers. Refer to Rear Brake Caliper Replacement in Disc Brakes.
9. Install the brake lines and the brake line bracket bolts to the axle.
10. Connect the parking brake cable. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side in Park Brake.
11. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
12. Connect the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.
13. Fill the axle with lubricant. Use the proper fluid. Refer to Approximate Fluid Capacities and Fluid and Lubricant Recommendations in Maintenance and Lubrication.
14. Remove the utility stands.
15. Lower the vehicle.

Rear Axle Replacement 35 Series

Important: Observe and accurately reference mark all driveline components relative to the propeller shaft and axles before disassembly. These components include the propeller shafts, the drive axles, the pinion flanges, the output shafts, etc. All components must be reassembled in the exact relationship to each other as they were when removed. In addition, published specifications and torque values, as well as any measurements made prior to disassembly must be followed.

1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
2. Place jack or utility stands (such as GMDE 123-B67313) at the front end of the vehicle.
3. Support the axle with jack stands.
4. Remove the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation .



5. Remove the stabilizer shaft link bolt (5) and the nut (3).
6. Disconnect the upper stabilizer shaft link (4) from the frame.



7. Reference mark the rear propeller shaft (3) to the rear axle pinion yoke (4).
8. Disconnect the propeller shaft from the axle.

Support the propeller shaft as necessary.




9. Disconnect the lower mount of the shock absorbers.



10. Disconnect the vent hose (1).
11. Disconnect the park brake cables. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side .



12. Disconnect the junction block.



13. Disconnect the brake pipe.



14. Disconnect the brake pipe fitting bracket from the brake assembly.
15. Remove the brake calipers. Refer to Rear Brake Caliper Replacement .

Notice: Support the brake caliper with heavy mechanic wire, or equivalent, whenever it is separated from its mount and the hydraulic flexible brake hose is still connected. Failure to support the caliper in this manner will cause the flexible brake hose to bear the weight of the caliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

16. Support the calipers from the frame using a heavy gage mechanics wire.



17. Remove the nuts and the washers from the spring assembly U-bolts.
18. Remove the U-bolts, the anchor plates and the spacers from the axle.
19. Remove the axle with the aid of a hydraulic assist.



20. Remove the stabilizer shaft U-bolt nuts (4) and the U-bolts (2) from the axle (3) (if necessary).
21. Remove the stabilizer shaft (1) from the axle (if necessary).

1. Install the stabilizer shaft (1) to the axle (3) (if necessary).
2. Install the stabilizer shaft clamps, the U-bolts (2), and the nuts (4) (if necessary).

Do not torque the stabilizer shaft U-bolt nuts at this time.

3. Place the axle under the vehicle.
4. Raise the axle to the springs with the aid of a hydraulic assist.

Align the axle with the springs.




5. Install the spacers, the anchor plates and the U-bolts.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

6. Install the washers if equipped and the nuts to the U-bolts.

Tighten
Tighten the nuts in a criss cross pattern to 150 N·m (110 lb ft).




7. Install the stabilizer shaft link to the frame (1) (if necessary).
8. Install the stabilizer shaft link bolt (5) and the nut (3) (if necessary).

Tighten

1. Tighten the stabilizer shaft link bolts to 95 N·m (70 lb ft).
2. Tighten the stabilizer shaft U-bolt nuts to 32 N·m (24 lb ft).
9. Install the brake calipers. Refer to Rear Brake Caliper Replacement .



10. Install the brake pipe fitting brackets.
11. Install the brake pipe fitting bracket bolts.

Tighten
Tighten the bolts to 22 N·m (16 lb ft).




12. Install the brake pipe.
13. Install the brake pipe bolts.

Tighten
Tighten the bolts to 22 N·m (16 lb ft).




14. Install the brake pipe junction block.
15. Install the brake pipe junction block bolt.

Tighten
Tighten the brake pipe junction block bolt to 22 N·m (16 lb ft).

16. Connect the park brake cables. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side .



17. Connect the vent hose (1) to the axle vent fitting.



18. Install the shock absorbers to the lower mount bracket.
19. Install the shock absorber bolts and the nuts.

Tighten
Tighten the shock absorber nuts to 95 N·m (70 lb ft).




20. Install the propeller shaft (3) to the pinion yoke (4).

Align the reference marks made during removal.

21. Install the propeller shaft yoke retaining clamps (2) and the bolts (1).

Tighten
Tighten the yoke retaining clamp bolts to 25 N·m (18 lb ft).

22. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation .
23. Fill the axle with lubricant. Use the proper fluid. Refer to Approximate Fluid Capacities and Fluid and Lubricant Recommendations .
24. Remove the jack and utility stands.
25. Lower the vehicle.

Rear Axle Replacement 15 Series with/RPO NYS

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Place jack stands at the front end of the vehicle in order to support the weight difference when the rear axle is removed.
3. Drain the axle lubricant from the rear axle. Refer to Lubricant Change .
4. Remove the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.
5. Remove the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
6. Disconnect the parking brake cables. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side in Park Brake.
7. Remove the left and right brake calipers from the brake caliper mounting brackets. Do not disconnect the hydraulic brake lines from the brake calipers. Refer to Rear Brake Caliper Replacement in Disc Brakes. Secure the left and the right brake calipers with mechanics wire to the leaf spring or the frame assembly.



8. Remove the 2 flex hose bracket bolts (1).
9. Remove the 2 brake pipe bracket bolts (2).
10. Remove the jounce bracket bolt (3).
11. Remove the brake pipe bracket nut (4). Secure the rear brake pipe assembly with mechanics wire to the under body and frame. Do not bend or kink the brake pipe assembly.
12. Disconnect the shock absorbers from the axle brackets. Refer to Shock Absorber Replacement in Rear Suspension.
13. Remove the vent hose from the rear axle vent fitting. Refer to Vent Hose Replacement .
14. Support the rear axle assembly with a suitable jack. Remove the nuts and the washers if equipped from the U-bolts.
15. Remove the U-bolts, the spring plates and the spacers from the axle assembly.
16. Lower the axle assembly.

1. Place the axle assembly onto the jack and place the rear axle assembly under the vehicle.
2. Align the rear axle assembly with the springs. Using the jack slowly raise the rear axle assembly into position.
3. Connect the spacers, the spring plates and the U-bolts to the rear axle.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

4. Install the washers if equipped and the nuts to the U-bolts.

Tighten
Tighten the nuts in a criss cross pattern to 150 N·m (110 lb ft).

5. Install the vent hose to the rear axle vent fitting. Refer to Vent Hose Replacement .
6. Connect the shock absorbers to the rear axle. Refer to Shock Absorber Replacement in Rear Suspension.



7. Remove the mechanics wire supporting the brake pipe assembly. Carefully position the brake pipe assembly onto the rear axle.
8. Install the brake pipe bracket nut (4).

Tighten
Tighten the nut to 13 N·m (115 lb in).

9. Install the jounce bracket bolt (3).

Tighten
Tighten the bolt to 12 N·m (106 lb in).

10. Install the 2 brake pipe bracket bolts (2).

Tighten
Tighten the bolts to 22 N·m (16 lb ft).

11. Install the 2 flex hose bracket bolts (1).

Tighten
Tighten the bolts to 12 N·m (106 lb in).

12. Remove the mechanics wire securing the brake calipers and install the brake calipers to the brake caliper mounting brackets. Refer to Rear Brake Caliper Replacement in Disc Brakes.
13. Connect the parking brake cable. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side in Park Brake.
14. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
15. Connect the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.
16. Fill the axle with lubricant. Use the proper fluid. Refer to Approximate Fluid Capacities and Fluid and Lubricant Recommendations in Maintenance and Lubrication.
17. Remove the jack stands.
18. Lower the vehicle.