Ford Pick-Ups/Bronco 1976-1986 Repair Guide

Front (4WD) and Rear Axles



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Differential fill plug location; Ford 8.8 in. rear axle shown. 4x4 front axle has a square-headed plug located on the differential cover

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 the front and rear axle housing every 24,000 miles, or every day if the vehicle is operated in deep water.

For the Ford 9 in. rear axle, remove the oil with a suction gun through the filler hole. On all other axles, loosen the differential cover bolts and let the fluid drain out. Refill the axle housings with the proper oil. Be sure to clean the area around the filler plug before removing the plug. See the section on level checks.