Instructions Step 1 - Place a large drain pan under the differential. Make sure it is larger than the differential and is able to hold all the gear lube in the differential. Allow the drain pan to stay in place until the job is finished to capture all gear lube. Step 2 - Begin by loosening all the bolts holding the differential cover. Loosen them approximately two turns each. Step 3 - Next, remove the bottom bolts. Step 4 - Carefully, so you don’t make a mess, take your pry bar or screwdriver and gently pry out on the bottom of the cover so it opens slightly. Allow the gear lube to slowly drain into the drain pan. Step 5 - Once the bulk of the oil has drained, remove the remaining bolts and remove the cover. Step 6 - Using a clean rag, wipe all remaining oil from the differential and clean the inside of the cover. NOTE: Some covers will have a magnet attached to it to collect metal shavings. Make sure to clean it too. Brake cleaner is a strong cleaner that is helpful in cleaning the dirty parts. However, make sure to use it in a well ventilated area. Step 7 - The old gasket material will need removed. Use a gasket scraper to clean both the differential housing and the cover. Make sure both surfaces are clean, dry, and free of old gasket material. Step 8 - Next, inspect the cover for any damage where the bolts held it in place. If it is warped, a leak can occur. Step 9 - Lay the differential cover on the floor (internal side facing up) and align the new gasket with the bolt holes. Place two of the bolts through the back side of the cover to hold the gasket in place. Step 10 - Carefully, align the bolts with the correct holes on the differential housing and hand tighten them. Step 11 - Install the remaining bolts hand tight. Step 12 - Using a star pattern, tighten the cover to the manufacturer’s recommended torque or snug. Step 13 - Remove the fill plug and refill the differential with the manufacturer’s recommended gear oil lube. Many require a standard GL-5. However, we recommend referring to the owner’s manual or service manual for manufacturer recommendations. Step 14 - The differential is full when the gear lube reaches the bottom of the filler hole. You will know because the gear lube will begin to leak back out. Once you think it is full, stop adding and allow the excess to leak from the filler hole. Replace the fill plug, clean up any gear lube from the work area, lower the vehicle, check for leaks, and the job is done. Although replacing the differential fluid isn’t required too often, it still needs to be done. We recommend following the manufacturer’s service intervals located in the vehicle owner’s manual. Also, make sure to dispose of the old gear lube properly. - By Joseph Felicia - AKA Jacobandnickolas Best Practices
- Look for a metallic sheen to the gear oil, this indicates there might be a bearing that has failed or is starting to fail.
- Inspect the wear pattern on the face of the ring and pinion gears teeth. The wear pattern should be in the middle of the tooth. If the wear pattern goes off the top tooth the gears are worn.