For servicing the rear axle shaft, use API GL-5, MIL-L-2105 B or C or equivalent with a viscosity rating of SAE 90 and make the switch to SAE 80 when temperatures are below 15degF (-10degC). Ensure the usage of oils with the correct additives for vehicles that have a limited slip differential. Check the fluid level at 10,000-mile (16,000 km) intervals by: Safely raising the vehicle, removing the rear axle shaft level plug, checking that the oil level is up to the plug hole, topping up if required, reinstalling the plug, and lowering the vehicle. Drain and refill the rear axle shaft housing every 100,000 miles (161,000 km) or after driving in high water. While some fluid can be removed by a suction gun, it is best practice to remove the back cover to get rid of contaminants. Begin by driving the vehicle until the lubricant is warmed to normal operating temperature and then safely raise and support the vehicle by means of jacks ensuring that the vehicle is level. Clean around the differential with a wire brush to prevent dirt contamination, place a drain pan under the rear axle shaft and loosen all but one or two of the retaining bolts on the rear cover. Carefully break the gasket seal and allow the lubricant to drain, and remove the final bolts and separate the cover. Clean the gasket mating surfaces of the cover and axle shaft housing, fit the rear cover with a new gasket and sealant, and tighten the bolts in a crisscross pattern. Check the vehicle to make sure it is level before adding the correct grade and amount of lubricant, then place the filler plug and lower the vehicle if needed and check for leaks after operation.