2011 Chevrolet Avalanche Owner's Manual - Page 388

10-32 Vehicle Care How to Check Lubricant The proper level is from 1.0 mm to 19.0 mm (0.04 in to 0.75 in) below the bottom of the filler plug hole, located on the rear axle. Add only enough fluid to reach the proper level. Also, if a vehicle has just been driven before checking the fluid level, it may appear lower than normal because fluid has traveled out along the axle tubes and has not drained back to the sump area. Therefore, a reading taken five minutes after the vehicle has been driven will appear to have a lower fluid level than a vehicle that has been stationary for an hour or two. Remember that the rear axle assembly must be supported to get a true reading. What to Use Refer to Recommended Fluids and Lubricants on page 11‑7 to determine what kind of lubricant to use. To get an accurate reading, the vehicle should be on a level surface.