The rear axle bearing on your Chevy truck is what supports the outside edge of the truck's axle and allows it to rotate freely. If this bearing fails, you may feel and/or hear a humming sound coming from the rear of the truck. In rare instances, a failed rear axle bearing that is left in for too long can build up enough heat to eventually weld itself in place in the axle housing, which may necessitate that the entire axle housing be replaced. Replacing the axle bearing is a job that, with the proper tools, you can do in your garage or front yard in a couple hours. This article describes how to replace the rear axle bearing on a Chevy truck with either an 8.5-inch or 9.5-inch differential.
Park your Chevy truck on a firm and level surface. Place blocks in front and behind one front wheel. Don't set the parking brake.
Slide the jack under the middle of the rear axle housing and lift the truck until the rear wheels clear the ground. Place jack stands, properly adjusted in height, under the axles and carefully lower the truck onto the stands.
Rotate the bolts on the rear axle housing cover counterclockwise with the ratchet and socket. These bolts will normally be ½-inch. Place the drain pan under the rear axle.
Carefully tap the screwdriver blade between the axle housing and cover near the bottom. Make sure drain pan is aligned properly to catch the gear oil as it drains. While holding the cover in place with one hand, twist and pry with the screwdriver to loosen the gasket on the housing. Allow the gear oil to drain.
Clean the inside and outside of the cover with rags and parts cleaner. Scrape the old gasket from the cover mating surfaces. Wipe the inside of the axle housing clean with a rag.
Slide out from under the truck. Push firmly in towards the centre on the axle flange. Slide back under the truck. Remove the C-lock from the end of the axle. Slide out and pull the axle out. Remove the seal and discard.
Close the jaws of the bearing puller and slide the arms into the axle housing, hooks facing outward. Rotate the wheel on the puller to spread the jaws, locking them behind the bearing.
Stand facing the puller and grasp the sliding hammer weight. Gently slide the weight until it rests near the axle. Violently push and throw the weight to the opposite side. Repeat until the bearing is removed.
Loosen the bearing arms and remove the bearing. Unscrew the puller from the slide hammer by turning it counterclockwise while holding the hammer shaft. Install the correct-sized bearing installer. Slide the bearing into the axle housing by hand and tap it in with the mallet. Center the bearing installer over the bearing with the hammer part at the end away from the axle. Push and throw the hammer against knob or plate at the base of the shaft until the new bearing is properly installed.
Install the seal, open side facing inward, by tapping it gently with the mallet until flush with the edge of the axle. Install the axle by sliding it gently into the housing, making sure the splines fully engage in the axle carrier in the differential.
Attach the C-lock to the end of the axle and push outward on the axle shaft to lock the clip in place. Apply a thin bead of RTV sealant to the cover-mating surface and press the gasket into the sealant making sure to line up the bolt holes properly. Apply another bead of sealant on the gasket.
Hold the cover in place with the bolt holes lined up and install the bolts by turning them clockwise by hand. Tighten these bolts to between 27 and 37 foot-pounds.
Remove the inspection plug from the differential. Most of these are removed by inserting the square drive of a ratchet into the plug and turning counterclockwise. Refill the differential with gear oil until the tip of your pinky is covered with gear oil when stuck into the filler opening. Replace the inspection plug and install by turning it clockwise by hand. Continue tightening it by turning clockwise with the ratchet until it won't turn anymore.
Replace the jack under the differential and lift the vehicle off the jack stands. Remove the jack stands. Lower the jack and pull it out from under the truck.
Instead of a special seal removal tool, you can wedge the tip of the axle under the seal and pry the seal out.
Wear safety glasses when under the truck to protect your eyes.