FLUID LEVEL CHECK
See Figure 1
Clean the area around the fill plug, which is located in the housing cover, 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 and use special limited slip differential additive.
DRAIN AND REFILL
Drain and refill the front and rear axle housing every 24,000 miles, or every day if the vehicle is operated in deep water. The best way to drain a Ford or Dana rear axle is to remove the cover. If desired, you may also remove the oil with a suction gun. Refill the axle housings with the proper oil. Be sure and clean the area around the drain plug before removing the plug. See the information on level checks.