A leak around a rear-end housing is not an uncommon event. Over time, excessive heat can cause the gasket between the rear end and the rear-end housing to crack or break. Once there is a crack or a break in the gasket, the gear oil inside of the rear-end housing will leak out through the faulty area of the gasket. The only way to stop the leak is to remove the rear end and replace the gasket.
Park the vehicle on a flat and level surface. Engage the parking brake. Place the wheel chocks in front of both front wheels and behind both front wheels.
Slide under the rear of the vehicle and locate the end of the drive shaft that is secured to the yoke on the front of the rear-end housing. Jack the rear of the vehicle up if necessary and place jack stands under the proper rear jacking points. Lower the vehicle evenly on top of the stands. Pull the jack out from under the vehicle. Mark the top of the drive-shaft yoke and the top of the rear-end yoke with a piece of chalk. This will ensure that the end of the drive shaft is reconnected properly to the rear-end housing yoke.
Loosen and remove the four U-joint strap bolts from the rear drive-shaft yoke that is attached to the rear-end yoke. Turn the strap bolts counter-clockwise with a ratchet and a socket to remove. Place the straps and the bolts in a safe area. Pull back on the drive shaft and lay the end of the drive shaft on the ground. Use a rubber mallet if necessary to tap the end of the drive shaft out of the rear-end yoke.
Place a drip pan underneath the drain plug on the rear-end housing. Loosen and remove the drain plug with the ratchet and a socket. Wait for all of the gear oil to drain out of the rear end. Leave the drain plug out.
Position the jack under the front of the rear-end housing. Jack the front of the jack up until it is touching the bottom of the rear-end housing. Loosen and remove all of the mounting bolts from the rear-end housing with the ratchet and a socket except for one bolt. Place the bolts in a safe area. Inspect the jack to ensure that it is secure under the front of the rear-end housing.
Slowly loosen the last mounting bolt from the housing. Remove the bolt and place it with the other bolts. Maneuver the rear-end housing so that it is sitting securely on top of the jack. Slowly lower the jack to the ground and slide the jack out from under the vehicle. Slowly pull the jack near the work table. Remove the front of the rear-end housing from the jack and place it on the work table.
Pull the old gasket off of the base of the front of the rear-end housing. Use a metal flat scraper to scrape all of the excess gasket off of the housing. Wipe down the area with a rag until it is clean and dry. Use a fine-grit sandpaper to lightly sand down the gasket area of the rear-end housing. Wipe down the gasket area again with a clean rag. Ensure that the gasket area is clean, smooth and dry.
Apply a thin bead of red high-temperature silicone around the gasket area of the rear-end housing. Press the new gasket onto the silicone and onto the gasket area. Maneuver the gasket until the holes of the gasket match the holes of the rear-end housing. Wait about 30 minutes for the silicone to dry. Place the front of the rear-end housing back onto the jack and roll it back under the vehicle.
Wipe down the facing of the rear-end housing with a clean rag. Use the flat scraper if necessary to remove any leftover gasket. Ensure that the facing of the rear-end housing is also clean, dry and smooth. Jack the front of the rear end up to the housing. Maneuver the rear end until the holes of the rear end match the holes of the housing. Screw all of the mounting bolts into the rear-end housing until they are tight with the ratchet and a socket. Lower the jack and pull it out from under the vehicle.
Finish tightening the mounting bolts down in an alternating sequence. Example: side to side and top to bottom. Once all of the bolts are tight, torque each mounting bolt down to 30- to 40-foot-pounds with a torque wrench and a socket. Reinstall the end of the drive shaft to the rear-end yoke with the U-joint straps and bolts. Torque the U-joint strap bolts down to 25- to 30-foot-pounds with the torque wrench and a socket.
Screw the drain plug back into the rear-end housing and tighten the plug down tight with the ratchet and socket. Loosen and remove the fill plug from the rear-end housing with the ratchet and socket. Place the end of the fluid pump hose into the fill-plug hole. Pump the gear oil into the rear end until the gear oil begins to run out of the fill hole. Pull the hose out of the hole and screw the fill plug back into the housing. Tighten the fill plug down tight with the ratchet and socket.
Jack the vehicle up and remove the jack stands. Lower the vehicle to the ground and remove the jack. Remove the wheel chocks and drive the vehicle around for about 10 minutes. Park the vehicle on a flat surface and engage the parking brake. Remove the fill hole and check the level of gear oil inside of the hole. If the oil is not dripping out of the hole, pump more gear oil into the housing until it flows out of the fill hole again. Screw the fill plug back into the housing and tighten it down tight with the ratchet and socket.
