2005 Chevrolet Avalanche Owner's Manual - Page 384

How to Check Lubricant What to Use Refer to the Maintenance Schedule to determine what kind of lubricant to use. See Recommended Fluids and Lubricants on page 6-13. Four-Wheel Drive Transfer Case It is not necessary to regularly check transfer case 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. Refer to the Maintenance Schedule to determine how often to change the lubricant. See Scheduled Maintenance on page 6-4. 1500 Series shown, 2500 Series similar To get an accurate reading, the vehicle should be on a level surface. The proper level for the 1500 Series is from 5/8 inch to 1 5/8 inch (15 mm to 40 mm) below the bottom of the filler plug hole. The proper level for the 2500 Series is from 0 to 1/2 inch (0 to 13 mm) below the bottom of the filler plug hole. Add only enough fluid to reach the proper level. 5-50