Envoy, Rainer, Trailblazer 2006-2007

Axle Unit


Removal & Installation

  1. Before servicing the vehicle, refer to the Precautions section.
  3. Support the rear axle housing. If a floor jack is being used, take care when removing the U-bolts to keep the axle from suddenly dislodging.
  5. Remove or disconnect the following:
    When disconnecting the brake lines from the wheel cylinders, immediately plug or cap the lines to prevent system contamination or excessive fluid loss.

    Rear wheels for clearance and to remove some weight from the axle housing
    Axle vibration dampener, if equipped
    Rear driveshaft from the pinion flange. Either remove the shaft completely from the vehicle or support it aside from the undercarriage using safety wire, but DO NOT allow the shaft to hang from the slip joint.
    Shock absorber-to-axle housing retainers, then swing the shock absorbers away from the axle housing
    Brake lines from the axle housing clips and the backing plates (wheel cylinders)

    Speed sensor connectors at the junction block, if applicable
    Parking brake cable(s)
    Axle housing-to-spring U-bolt nuts, washers, U-bolts and the anchor plates
    Vent hose from the top of the axle housing
    Axle with the help of an assistant by moving it to clear the leaf spring


To install:

  1. With the help of an assistant, carefully position the rear axle into the vehicle.

    Click image to see an enlarged view

    Fig. Exploded view of the rear axle mounting

  3. Install or connect the following:

    Vent hose to the axle housing

  5. Be sure the housing is properly positioned on the leaf spring, then loosely install the U-bolts, anchor plates, washers and nuts.

    Tighten the U-bolt nuts in a cross pattern to 18 ft. lbs. (25 Nm) to made sure everything is evenly seated. Then tighten the nuts in steps to 74 ft. lbs. (100 Nm).
    Brakes lines secure them to the axle housing
    Parking brake cable(s), if removed
    Speed sensor connectors to the junction block, if equipped
    Driveshaft assembly
    Shock absorbers to the lower mounts, then tighten the mount nuts
    Axle vibration dampener, if equipped
    Tire/wheel assemblies

  7. Bleed the hydraulic brake system.
  9. Check the fluid level in the rear axle assembly and add, as necessary. Make sure the vehicle is level when checking and adding fluid.