Ford 9 inch Differential Fill Plug

New replacement fill plug for your Ford 9 inch rear end differential.

Where is the oil fill plug on a Ford 9 inch differential? The oil fill plug on your Ford 9 inch rear end is located on the left hand or driver side of your Ford 9 inch differential case just in front of where the drop-in mates to the differential housing.

How much oil should be used in a Ford Bronco 9 inch rear end? The oil capacity of the early Ford Bronco rear differential varies by housing and differential angle among other factors. The simple answer is to fill the differential until the oil starts to drip from the fill hole. This will be more oil than is necessary but ensures you will have enough and will have no negative effects on the rear end.

What type of oil should be used in the early Bronco rear Ford 9 inch? We recommend standard 80/90 weight gear oil for your Ford 9 inch rear end. If you have a clutch driven limited slip such as a track lock or power lock, be sure to add friction modifier or use oil with friction modifier built in.