On 1989-93 models, use hypoid gear lubricant SAE 80 or 90.
On 1994-96 models use a premium rear axle lubricant.
On Dana limited slip axles, add 4oz. of friction modifier, Ford specification No. EST-M2C118-A, its equivalent or superseding fluid.
On Ford axles, add 4oz. of friction modifier, Ford specification No. EST-M2C118-A, its equivalent or superseding fluid.
FLUID LEVEL CHECK
See Figures 1, 2 and 3
Clean the area around the fill plug, which is located in the housing cover on the Dana axles and the carrier casting on the Ford axles, before removing the plug. The lubricant level should be maintained to the bottom of the fill hole with the axle in its normal running position. If lubricant does not appear at the hole when the plug is removed, additional lubricant should be added. Use hypoid gear lubricant SAE 80 or 90.
If the differential is of the limited slip type, be sure to use special limited slip differential additive.
DRAIN & REFILL
See Figures 4 through 8
Drain and refill the rear axle housing every 100,000 miles (160,000 km) or any time the vehicle is driven in high water (up to the axle). Although some fluid can be removed using a suction gun, the best method is to remove the rear cover to ensure that all of any present contaminants are removed. As with any fluid change, the oil should be at normal operating temperature to assure the best flow and removal of fluid/contaminants.
- Drive the vehicle until the lubricant reaches normal operating temperature.
- If necessary for access, raise and support the vehicle safely using jackstands, but be sure that the vehicle is level so you can properly refill the axle when you are finished.
- Use a wire brush to clean the area around the differential. This will help prevent dirt from contaminating the differential housing while the cover is removed.
- Position a drain pan under the rear axle.
- Loosen and remove all but 2 of the rear cover upper or side retaining bolts. The remaining 2 bolts should then be loosened to within a few turns of complete removal. Use a small prytool to carefully break the gasket seal at the base of the cover and allow the lubricant to drain. Be VERY careful not to force or damage the cover and gasket mating surface.
- Once most of the fluid has drained, remove the final retaining bolts and separate the cover from the housing.
- Carefully clean the gasket mating surfaces of the cover and axle housing of any remaining gasket or sealer. A putty knife is a good tool to use for this. You may want to cover the differential gears using a rag or piece of plastic to prevent contaminating them with dirt or pieces of the old gasket.
- Install the rear cover using a new gasket and sealant. Tighten the retaining bolts using a crisscross pattern.
Make sure the vehicle is level before attempting to add fluid to the rear axle, otherwise an incorrect fluid level will result.
- Refill the rear axle housing using the proper grade and quantity of lubricant. Install the filler plug, operate the vehicle and check for any leaks.