GMC 20937821 Axle Assembly, Rear (3.42 Ratio)

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It is important to inspect the boots periodically for damage and leaking lubricant, as torn CV joint boots must be replaced immediately to prevent damage to the joints.

The optional locking limited-slip rear axle slows the rotation of the differential case when one wheel loses traction.

The next step is to drain the differential lubricant and remove the differential cover.

To remove and install components in the front differential for AWD systems, follow these steps: Remove the stabilizer bar link and, if applicable, the front shock absorber. Unbolt the right driveaxle from the axleshaft flange, supporting it properly. Support the differential carrier with a floor jack and a block of wood. Remove nuts attaching the axle shaft to its support bracket and the bolts securing the axle shaft flange to the differential carrier. Use a brass punch and hammer to separate the axle shaft from the differential case side gear. Remove the inner axle shaft assembly and axle shaft. Replace the inner seal and bearing with a special tool, then apply RTV sealant to the differential sealing surface and install the inner axle shaft housing assembly. Install the axle shaft to the support bracket and align the splines with the differential side gear. Tap the axle shaft with a mallet until the ring (clip) aligns with the groove in the differential case side gear. Install the axle shaft to the inner flange and tighten the bolts. Reinstall the stabilizer link, fill the differential with lubricant, install the differential carrier splash shield, and finally, install the wheel and lug nuts. Lower the vehicle, tighten the lug nuts, and check for proper operation.

After installing the rear axle assembly, the brakes should be bled, the wheels and lug nuts should be installed, and the vehicle should be lowered. Finally, the lug nuts should be tightened to the proper torque specification.

The vehicle has a hypoid, semi-floating type rear axle assembly.

The driveaxle/hub nut (new) and the flange bolts should be tightened to the torque values specifications during installation.

To remove and install components in the front differential for 4WD systems, follow these steps: Remove the bolts securing the axle tube to the differential carrier and the nuts attaching the tube to its support bracket. Carefully remove the output shaft tube, ensuring no components fall out. Mount the tube in a vise and remove the internal components. Measure and remove the axleshaft bearing using a slide hammer and bearing remover attachment. For installation, install the bearing to the original depth using a bearing driver or socket, then install a new seal and deflector, lubricating the seal lips with grease. Carefully drive in the axleshaft, followed by the internal components. Apply RTV sealant to the tube-to-differential housing mating surface, and install the tube assembly, tightening bolts and nuts to specified torques. Reinstall the driveaxle, front axle shift motor, and fill the differential with lubricant.

The initial steps are to loosen the wheel lug nuts, raise the front of the vehicle, and support it securely on jackstands.

After raising the vehicle and supporting it on jackstands, a jack should be positioned under the rear axle differential housing.

It is also important to check the driveaxle shafts for cracks, dents, and distortion.

To install a full-floating axle shaft, you should hold the axleshaft level to engage the splines and use a new gasket on the flange. Finally, tighten the flange bolts to the proper torque specifications.