Your Ford transit van has a differential that transfers horizontal rotational power from the drive shaft to lateral motion. This lateral motion is transmitted to the rear drive shaft of your vehicle. The differential contains gearing that provides the proper torque for each wheel and requires oil to maintain lubrication so the the gears do not overheat or run metal to metal as this will cause failure of the gearing system. Changing the differential oil is an easy task for do-it-yourselfers.
Allow the van to completely cool down.
Locate the differential at the rear of the drive shaft.
Place the oil drain pan under the drain plug at the back of the differential.
Remove the drain plug, turning the 3/4-inch wrench counterclockwise.
Allow all used oil to drain out until just an occasional drip remains.
Pour the oil into the drain/fill plug opening and check the level with your finger. Once the oil reaches the point where you can feel it with the tip of your finger, the gear box is full.
Replace the drain plug with your 3/4-inch wrench by turning it clockwise until tight.
