Proper lubrication is necessary for drive axle durability. Different applications require different gear lubes. The
American Petroleum Institute (API) has established a rating system for the various gear lubes available. In general,
rear axles use either SAE 80- or 9O-weight gear oil for lubrication, meeting API GL-4 or GL-5 specifications. With
limited-slip axles, it is very important that the proper gear lube be used. Most often, a special friction modifier fluid
should be added to the fluid. If the wrong lubricant is used, damage to the clutch packs and grabbing or chattering
on tums will result. If this condition exists, try draining the oil and refilling with the proper gear lube before servicing it.