Rear Axle Replacement 15/25 Series Pickup, 25 Series Util

1. Raise and support the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
2. Drain the axle lubricant from the rear axle. Refer to Lubricant Change .
3. Disconnect the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement .
4. Remove the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
5. Disconnect the parking brake cable. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side in Parking Brake.
6. Remove the brake calipers. Refer to Rear Brake Caliper Replacement in Disc Brakes.
7. Disconnect the shock absorbers from the axle brackets. Refer to Shock Absorber Replacement in Rear Suspension.
8. Remove the vent hose from the rear axle vent fitting. Refer to Vent Hose Replacement .
9. Remove the nuts and the washers from the U-bolts.
10. Remove the U-bolts, the spring plates and the spacers form the axle assembly.
11. 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 and the nuts to the U-bolts.

Tighten

•	Tighten the nuts to 80 N·m (59 lb ft).

•	Tighten the nuts to 120 N·m (89 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. Connect the parking brake cable. Refer to Parking Brake Rear Cable Replacement - Left Side and Parking Brake Rear Cable Replacement - Right Side in Parking Brake.
10. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
11. Connect the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.
12. Fill the rear axle to the following levels. Refer to Fluid and Lubricant Recommendations in Maintenance and Lubrication.

•	8.6 inch ring gear rear axles 15-40mm (0.6 in-1.6 in) below the fill plug.

•	9.5 and 10.5 inch ring gear rear axles 10 mm (0.4 in) below the fill plug.

13. Bleed the brake system. Refer to Antilock Brake System Automated Bleed Procedure .
14. Remove the supports and lower the vehicle.

Rear Axle Replacement 15 Series Utility

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. Support the rear axle with jack stands.
4. Remove the wheel and tire assemblies. Refer to Tire and Wheel Removal and Installation in Wheels and Tires.
5. Disconnect the rear axle vent tube.
6. Remove the propshaft. Refer to Two-Piece Propeller Shaft Replacement in Propeller Shaft.
7. Disconnect the left rear parking brake cable from the rear axle. Refer to Parking Brake Rear Cable Replacement - Left Side in Park Brake.
8. Disconnect the right rear parking brake cable from the rear axle. Refer to Parking Brake Rear Cable Replacement - Right Side in Park Brake.
9. Remove the caliper assemblies from the rear axle. Refer to Rear Brake Caliper Replacement in Disc Brakes.
10. Remove the crossover brake pipe from the rear axle.
11. Remove the coil springs. Refer to Coil Spring Replacement in Rear Suspension.
12. Disconnect the track bar from the rear axle. Refer to Rear Axle Tie Rod Replacement in Rear Suspension.
13. Disconnect the lower control arm from the rear axle. Refer to Rear Axle Lower Control Arm Replacement in Rear Suspension.
14. Disconnect the upper control arm from the rear axle. Refer to Rear Axle Upper Control Arm Replacement in Rear Suspension.
15. Remove the rear axle assembly from the vehicle.

1. Install the rear axle assembly to the vehicle.
2. Connect the upper control arm to the rear axle. Refer to Rear Axle Upper Control Arm Replacement in Rear Suspension.
3. Connect the lower control arm to the rear axle. Refer to Rear Axle Lower Control Arm Replacement in Rear Suspension.
4. Connect the track bar to the rear axle. Refer to Rear Axle Tie Rod Replacement in Rear Suspension.
5. Install the coil springs. Refer to Coil Spring Replacement in Rear Suspension.

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 crossover brake pipe to the rear axle.

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

7. Install the caliper assemblies to the rear axle. Refer to Rear Brake Caliper Replacement in Disc Brakes.
8. Connect the right rear parking brake cable to the rear axle. Refer to Parking Brake Rear Cable Replacement - Right Side in Park Brake.
9. Connect the left rear parking brake cable to the rear axle. Refer to Parking Brake Rear Cable Replacement - Left Side in Park Brake.
10. Install the propshaft. Refer to Two-Piece Propeller Shaft Replacement in Propeller Shaft.
11. Connect the rear axle vent tube.
12. Install the wheel and tire assemblies. Refer to Tire and Wheel Removal and Installation in Wheels and Tires.
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 and jack stands.
15. Lower the vehicle.