GMC 15938629 AXLE

Loosen the rear wheel lug nuts, raise the rear of the vehicle and support it securely on jackstands placed under the frame rails. Block the front wheels to keep the vehicle from rolling off the stands. Remove the rear wheels. Drain the rear axle lubricant. Disconnect the driveshaft from the rear axle pinion flange. Fasten the driveshaft out of the way with a piece of wire from the underbody. Position a jack under the rear axle differential housing, then raise it slightly. Disconnect the shock absorbers at their lower mounts, then lower the jack far enough so the leaf springs aren't compressed at all. Disconnect the vent hose from the fitting on the axle housing and fasten it out of the way. Disconnect the flexible brake hose from the junction block on the axle housing, then plug the hose to prevent fluid leakage. Remove the brake drums. Remove the bolts securing the parking brake cables to the rear leaf springs, then disconnect the parking brake cables from the parking brake mechanism at the brake shoes. With a jack under the differential for support, remove the leaf spring LI-bolts. With the help of an assistant, maneuver the rear axle over the leaf springs, rotate it to clear the springs, then remove the rear axle assembly from under the vehicle. Installation is the reverse of removal. Tighten the U-joint strap bolts to the specific torque. Tighten all suspension fasteners to the specific torque values. Tighten the brake fasteners to the specific torque. Bleed the brakes. Install the wheels and tighten the lug nuts to the specific torque.

Loosen the rear wheel lug nuts and raise the rear of the vehicle. Support it securely on jackstands and block the front wheels. Remove the wheel and brake drum. Remove the differential cover and allow the lubricant to drain into a container. Remove the lock bolt. On models with a conventional differential, remove the pinion shaft. On models with a locking differential, withdraw the pinion shaft part way, then rotate the differential until the shaft touches the case. Have an assistant push in on the outer flanged end of the axleshaft while you remove the C-lock from the groove in the inner end of the shaft. With the C-lock removed, withdraw the axleshaft, taking care not to damage the oil seal. Some models have a thrust washer in the differential; make sure it doesn't fall out when the axleshaft is removed. To install, carefully insert the axleshaft into the housing and seat it securely in the differential. Install the C-lock in the axleshaft groove and pull out on the flange to lock it. Insert the pinion shaft, align the hole in the shaft with the lock bolt hole and install the lock bolt. Check the cover gasket and replace if necessary. Install the cover and tighten the bolts. Fill the differential with the specified lubricant. Install the brake drum, wheel, and lug nuts. Lower the vehicle and tighten the lug nuts.

Power is transmitted from the front differential/axle to the front wheels through a pair of axle shafts. The inner end of the axle shafts are splined to the differential side gears. The outer end of each axle shaft has a stub shaft that is splined to the front hub and bearing assembly and locked in place with a large nut. The inner ends of the axle shafts are equipped with sliding constant velocity (CV) joints, which are capable of both angular and axial motion. Each inner CV joint assembly consists of a ball-and-cage type bearing and a housing in which the joint is free to slide in--and-out as the axle shaft moves up-and-down with the wheel. The outer ends of the axle shafts are also equipped with ball-and-cage type CV joints, which are capable of angular but not axial movement. Each outer CV joint consists of six caged ball bearings running between an inner race and the housing. The boots should be inspected periodically for damage and leaking lubricant. Torn CV joint boots must be replaced immediately or the joints will be damaged. If either boot of an axle shaft is damaged, that axle shaft must be removed in order to replace the boot. Should a boot be damaged, the CV joint can be disassembled and cleaned, but if any parts are damaged, the entire axle shaft assembly must be replaced as a unit. The most common symptom of worn or damaged CV joints, besides lubricant leaks, is a clicking noise in turns, a clunk when accelerating after coasting and vibration at highway speeds. To check for wear in the CV joints and axle shafts, grasp each axle (one at a time) and rotate it in both directions while holding the CV joint housings, feeling for play indicating worn splines or sloppy CV joints. Also check the axle shafts for cracks, dents and distortion.

Power is transmitted from the front differential/axle to the front wheels through a pair of axle shafts. The inner end of the axle shafts are splined to the differential side gears. The outer end of each axle shaft has a stub shaft that is splined to the front hub and bearing assembly and locked in place with a large nut. The inner ends of the axle shafts are equipped with sliding constant velocity (CV) joints, which are capable of both angular and axial motion. Each inner CV joint assembly consists of a ball-and-cage type bearing and a housing in which the joint is free to slide in--and-out as the axle shaft moves up-and-down with the wheel. The outer ends of the axle shafts are also equipped with ball-and-cage type CV joints, which are capable of angular but not axial movement. Each outer CV joint consists of six caged ball bearings running between an inner race and the housing. The boots should be inspected periodically for damage and leaking lubricant. Torn CV joint boots must be replaced immediately or the joints will be damaged. If either boot of an axle shaft is damaged, that axle shaft must be removed in order to replace the boot. Should a boot be damaged, the CV joint can be disassembled and cleaned, but if any parts are damaged, the entire axle shaft assembly must be replaced as a unit. The most common symptom of worn or damaged CV joints, besides lubricant leaks, is a clicking noise in turns, a clunk when accelerating after coasting and vibration at highway speeds. To check for wear in the CV joints and axle shafts, grasp each axle (one at a time) and rotate it in both directions while holding the CV joint housings, feeling for play indicating worn splines or sloppy CV joints. Also check the axle shafts for cracks, dents and distortion.

The hypoid, semi-floating rear axle assembly has a differential that permits the outer rear wheel to turn faster than the inner wheel while rounding corners. Through splining, the axleshafts can accommodate this speed variance with the differential side gears. Locking limited-slip rear axle is optional; such an axle acts as a conventional differential but contains multi-disc clutch packs that help in equalizing wheel rotation under low-traction conditions. A fully independent front axle assembly for the 4WD models consists of a differential and two driveaxles with inner and outer constant velocity (CV) joints. There are other causes which should be checked before thinking about axles: among them road noise, conditions of tires, or engine or transmission noise as they appear similar to axle problems . Thus, when it comes to performing any major overhaul on a differential, one may require special tools and this is not cost effective for do-it-yourselfers due to limitations in repairing procedures' scope-axleshaft-related tasks only like removing, installing, oil seal replacing, bearing replacing or removing of the whole unit for professional repair or replacement.

The next step is to remove the front wheel.

No, overhauling the differential typically requires special tools and is not cost-effective for DIY work.

To prevent the hub from rotating, you can brace a large prybar across two of the wheel studs or insert a long punch or screwdriver through the window in the brake caliper and into the disc cooling vanes.

Insert the pinion shaft, align the hole in the shaft with the lock bolt hole, and install the lock bolt.

Before removing the rear axle assembly from under the vehicle, you should disconnect the shock absorbers at their lower mounts, disconnect the vent hose from the fitting on the axle housing, and disconnect the flexible brake hose from the junction block on the axle housing (and plug the hose to prevent fluid leakage).