2010 Chevrolet Silverado 1500 Regular Cab Owner's Manual - Page 493

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. How to Check Lubricant All Other Series and Engines To get an accurate reading, the vehicle should be on a level surface. . For all 4.3L, 4.8L and 5.3L 1500 Series applications, the proper level is 0.04 inches to 0.75 inches (1.0 mm to 19.0 mm) below the bottom of the filler hole, located on the rear axle. Add only enough fluid to reach the proper level. For all 6.0L and 6.2L 1500 Series applications, the proper level is from 0.6 inches to 1.6 inches (15 mm to 40 mm) below the bottom of the filler plug hole, located on the rear axle. Add only enough fluid to reach the proper level. 6-49 . 2500HD with 6.0L and 6.2L