FLUID RECOMMENDATIONS
Use SAE 90 weight hypoid gear oil for standard differential units (non-limited slip or Traction-Lok differentials). Traction-Lok (limited slip) axle assemblies require E0AZ-19580-A Limited Slip lubricant and 4 oz. of friction modifier (Ford No. C8AZ-19B546-A) or their equivalents. Always ensure that the fluid being added is clean.
LEVEL CHECK
Fig. Fig. 1 Rear axle fill plug location
The rear axle fluid level should be checked at regular intervals. With the car standing perfectly level, apply the parking brake, set the transmission in Park or 1st gear, stop the engine and block all four wheels. Wipe all dirt and grease from the filler plug area. Use a 3 / 8 " flex-bar, T-handle or ratchet to remove the filler plug. (Some models may require an adjustable wrench.) The fluid level must be maintained at 1 / 2 in. from the bottom of the filler plug hole.
To check the fluid level in the axle, bend a clean, straight piece of wire to a 90° angle and insert the bent end of the wire into the axle while resting it on the lower edge of the filler hole. Top up as necessary with the proper lubricant, using a suction gun or kitchen baster. Install the filler plug.
DRAIN & REFILL
Rear Axles With Drain Plugs
Fig. Fig. 2 To drain the rear differential, first loosen the fill plug ...
Fig. Fig. 3 ... then clean all dirt and grime from the differential cover
Fig. Fig. 4 Remove all but two (which should just be loosened) of the cover mounting bolts ...
Fig. Fig. 5 ... and gently pry the cover away from the differential case to drain the oil
Fig. Fig. 6 After a few minutes, remove the two loose bolts and allow the remainder of the oil to drain
Fig. Fig. 7 Install the cover with a new gasket, then fill the differential with gear oil through the fill hole
- Block the front wheels, then raise and safely support the rear of the vehicle on jackstands.
- Remove all dirt from around the differential drain and fill plugs with a wire brush, then remove the differential fill plug.
- Position a large catch pan under the differential, then remove the drain plug and allow the oil to empty into the pan.
- Once all of the differential oil has drained, install the drain plug and tighten it until secure.
- Using SAE 90 weight hypoid gear oil for standard differential units, or E0AZ-19580-A Limited Slip lubricant and 4 oz. of friction modifier (Ford No. C8AZ-19B456-A or equivalent) for Traction-Lok limited slip rear differential units, fill the differential case through the fill plug. The oil level should be even with the bottom of the fill plug hole.
- Install the fill plug securely.
- Lower the vehicle and remove the front wheel blocks.
- Block the front wheels, then raise and and safely support the rear of the vehicle on jackstands.
- Remove all dirt from around the differential fill plug and cover bolts with a wire brush, then remove the differential fill plug.
- Position a large catch pan under the differential unit, then remove all of the cover mounting bolts, except for the top bolt. Slow loosen the top bolt and separate the cover from the case with a small prytool to drain the differential oil. Allow the oil to empty into the catch pan.
- Remove the top bolt and differential cover from the case.
- Cover the differential gears with a clean shop rag, then clean the cover-to-case mounting surfaces of all old gasket material or dirt. Remove the shop rag from the differential unit.
- Install the differential cover, along with a new gasket, and tighten the mounting bolts securely and evenly in a crisscross pattern.
- Using SAE 90 weight hypoid gear oil for standard differential units, or E0AZ-19580-A Limited Slip lubricant and 4 oz. of friction modifier (Ford No. C8AZ-19B456-A or equivalent) for Traction-Lok limited slip rear differential units, fill the differential case through the fill plug. The oil level should be even with the bottom of the fill plug hole.
- Install the fill plug securely.
- Lower the vehicle and remove the front wheel blocks.
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