2011 Chevrolet Express 1500 Cargo Owner's Manual - Page 302

10-32 Vehicle Care What to Use Refer to Recommended Fluids and Lubricants on page 11‑8 to determine what kind of lubricant to use. 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 on page 11‑3. How to Check Lubricant To get an accurate reading, the vehicle should be on a level surface. If the level is below the bottom of the fill plug hole, some lubricant may need to be added. When the differential is cold, add enough lubricant to raise the level to 10 mm (3/8 in) below the fill plug hole. When the differential is at operating temperature (warm), add enough lubricant to raise the level to the bottom of the fill plug hole. Rear Axle When to Check Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant. See Scheduled Maintenance on page 11‑3.