GMC 22890840 Rear Axle Assembly

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The rear axle assembly of the vehicle is a hypoid, semi-floating type with a differential that allows the outer rear wheel to turn at a higher speed than the inner tire when going around a corner. An optional locking limited-slip rear axle is also available, which slows the rotation of the differential case when one wheel loses traction. On 4WD models, a fully independent front axle assembly is used with an extension axle shaft on the right side to make up the difference in distance between the differential and the right front wheel. When diagnosing axle problems, it is important to check for other possible causes such as road or tire noise, and to isolate engine and transmission noises. Overhauling the differential requires special tools and is not cost-effective for a do-it-yourselfer.

To remove the rear axle assembly from a vehicle, first loosen the rear wheel lug nuts, raise the rear of the vehicle, and support it securely on jackstands. Then, position a jack under the rear axle differential housing and remove the driveshaft, shock absorbers, vent hose, brake hose, rear brake assemblies, parking brake cables, and rear wheel speed sensors. For leaf spring models, disconnect the spring U-bolts and remove the springplates before lowering the jack under the differential and removing the rear axle assembly. For coil spring models, detach the links for the electronic suspension control sensors, detach the track bar from the rear axle, remove the stabilizer bar, remove the coil springs, and disconnect the upper and lower trailing arms from the axle assembly before lowering the jack under the differential and removing the rear axle assembly. To install the rear axle assembly, follow the reverse order of removal and tighten all suspension and brake fasteners to the torque value specifications. Finally, bleed the brakes, install the wheels and lug nuts, lower the vehicle, and tighten the lug nuts to the proper torque specification.

The initial steps to remove and install components in the front differential of selectable 4WD systems are as follows: Loosen the wheel lug nuts. Raise the vehicle securely on jackstands. Remove the right front wheel. Remove the differential carrier splash shield if equipped. Drain the lubricant from the front differential. For 4WD systems, unbolt the right driveaxle from the axleshaft flange and support it out of the way. Remove the front axle shift motor and, if applicable, disconnect the front stabilizer link or remove the front shock absorber/coil spring assembly. On 2500/3500 models, remove the front axle bracket bolts and slide the bracket forward for additional clearance. Support the differential carrier with a floor jack and a block of wood.

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.

For leaf spring models, the spring U-bolts should be disconnected, followed by removing the springplates. Then, the jack can be lowered under the differential to remove the rear axle assembly.

After removing the differential cover, you need to remove the pinion shaft lock screw and withdraw the pinion shaft.

If the vehicle has a differential carrier splash shield, it should be removed after removing the driveaxle/hub nut.

The differential allows the outer rear wheel to turn at a higher speed than the inner tire when going around a corner.

The initial steps to remove and install components in the front differential of selectable 4WD systems are as follows:Loosen the wheel lug nuts.

For leaf spring models, the spring U-bolts should be disconnected, followed by removing the springplates. Then, the jack can be lowered under the differential to remove the rear axle assembly.

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

To remove the semi-floating axle shaft, you need to remove the C-lock from the groove on the inner end of the axleshaft and withdraw the shaft, being careful not to damage the oil seal.

To install the semi-floating axle shaft, you should insert the axleshaft into the housing until it engages with the differential side gear, install the C-lock, and insert the pinion shaft.

The outer ends of the driveaxles have a stub shaft that is splined to the front hub and bearing assembly and locked in place with a large nut.

Before installing the driveaxle, the splines on the stub shaft should be lubricated with multi-purpose grease.

In 4WD models, an extension axle shaft is used on the right side to make up the difference in distance between the differential and the right front wheel.

The initial steps to remove and install components in the front differential of selectable 4WD systems are as follows: Loosen the wheel lug nuts. Raise the vehicle securely on jackstands. Remove the right front wheel. Remove the differential carrier splash shield if equipped. Drain the lubricant from the front differential. For 4WD systems, unbolt the right driveaxle from the axleshaft flange and support it out of the way. Remove the front axle shift motor and, if applicable, disconnect the front stabilizer link or remove the front shock absorber/coil spring assembly. On 2500/3500 models, remove the front axle bracket bolts and slide the bracket forward for additional clearance. Support the differential carrier with a floor jack and a block of wood.

If a boot is damaged, the CV joint can be disassembled and cleaned, but if any parts are damaged, the entire driveaxle assembly must be replaced as a unit.

Before removing a semi-floating axle shaft, you should loosen the rear wheel lug nuts and raise the vehicle on jackstands.

The final step is to tighten the wheel lug nuts to the proper torque specifications.

When diagnosing axle problems, it is important to check for other possible causes such as road or tire noise, and to isolate engine and transmission noises.

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 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.