It is not necessary to regularly check rear axle fluid unless you suspect there is a leak or you hear an unusual noise. A fluid loss could indicate a problem. Have it inspected and repaired.

To get an accurate reading, the vehicle should be on a level surface.

For all vehicles, excluding vehicles equipped with the 6.0L V8 engine, the proper level is from 0 to 0.40 inch (0 to 10 mm) below the bottom of the filler plug hole, located on the rear axle.

For vehicles equipped with the 6.0L V8 engine, the proper level is from 0.6 inch to 1.6 inches (15 mm to 40 mm) below the bottom of the filler plug hole, located on the rear axle differential cover.

Add only enough fluid to reach the proper level.

To determine what kind of lubricant to use, see Recommended Fluids and Lubricants .