2007 GMC Savana Van Owner's Manual - Page 331

Rear Axle When to Check Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant. See Scheduled Maintenance (Gasoline Engine) on page 399. If you have the 1500 Series, the proper level is from 5/8 inch (15 mm) to 1 5/8 inch (40 mm) below the bottom of the filler plug hole. The proper level for the 2500 and 3500 Series is from 0 to 1/4 (6 mm) below the bottom of the filler plug hole. Add only enough fluid to reach the proper level. 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 409. Front Axle When to Check and Change Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant and when to change it. See Scheduled Maintenance (Gasoline Engine) on page 399. To get an accurate reading, the vehicle should be on a level surface. 331