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 .

For vehicles equipped with the SS package, to add lubricant when the level is low, use SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 12378261, in Canada 10953455) meeting GM Specification 9986115. To completely refill after draining, add 5.5 ounces (163 ml) of Limited-Slip Axle Lubricant Additive (GM Part No. U.S. 1052358, in Canada 992694). Then fill to the bottom of the filler plug hole with the Synthetic Gear Lubricant.