SAE 90 weight hypoid gear oil is required. If equipped with Traction-Lok differential, the addition of friction modifier additive C8AZ-19B546-A or equivalent, is also required when draining and refilling.
See Figure 1
Checking the differential fluid level is generally unnecessary unless a leak is suspected.
- Raise and safely support the entire vehicle on jackstands. Refer to the Jacking procedure in this section.
- Remove the oil fill plug from the differential housing. The hex drive on a 3 / 8 in. drive ratchet, breaker bar or extension works well on most applications.
- Insert a finger into the fill hole; be careful as the threads may be sharp. The oil level should be about 1 / 4 in. (6mm) below the bottom of the fill hole.
- If the oil level feels low, add oil through the fill hole. Most hypoid gear oils come in squeeze bottles equipped with small fill nozzles, designed for this purpose.
- When the oil level is correct, install the oil fill plug and tighten to 15-30 ft. lbs. (20-41 Nm).
DRAIN AND REFILL
See Figures 2, 3, 4, 5 and 6
The differential should be drained and refilled every 100,000 miles (161,000 km) or if the axle has been submerged in water.
- Raise and safely support the vehicle on jackstands. Refer to the Jacking procedure in this section.
- Clean all dirt from the area of the differential cover.
- Position a drain pan under the differential.
- Loosen and remove all the cover retaining bolts except 2. Allow the fluid to drain from the differential.
- Remove the remaining bolts, then remove the differential cover. Cover the differential carrier with a clean rag to prevent axle contamination, then clean all the old sealant from the machined surface of the differential housing.
- Make sure the machined surfaces of the cover and differential are clean and free of oil. Apply a 1 / 4 in. (6mm) wide bead of silicone sealer around the inside circumference of the cover.
- Install the cover with the retaining bolts. Tighten the bolts evenly to 25-35 ft. lbs. (34-47 Nm) in a crisscross pattern.
- Remove the oil fill plug and add the required amount of hypoid gear oil through the oil fill hole. Refer to the Capacities chart at the end of this section.
If equipped with a Traction-Lok differential, 4 oz. of friction modifier additive C8AZ-19B546-A or equivalent, must be included in the refill.
- Install the oil fill plug and tighten to 15-30 ft. lbs. (20-41 Nm). Lower the vehicle.
- Road test the vehicle to warm the fluid. Check for leaks.