2011 GMC Savana 3500 Passenger Owner's Manual - Page 300

10-34 Vehicle Care What to Use Refer to Recommended Fluids and Lubricants on page 11‑7 to determine what kind of lubricant to use. Extended Storage: Remove the black, negative (−) cable from the battery or use a battery trickle charger. All-Wheel Drive Transfer Case When to Check Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant. See Scheduled Maintenance on page 11‑2. How to Check Lubricant To get an accurate reading, the vehicle should be on a level surface. 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 11‑2. If the level is below the bottom of the filler plug hole, some lubricant will need to be added. Add enough lubricant to raise the level to the bottom of the filler plug hole. Use care not to overtighten the plug.