2007 GMC Acadia Owner's Manual - Page 430

All-Wheel Drive Be sure to perform the lubricant checks described in this section. There are two additional systems that need lubrication. How to Check Lubricant Transfer Case When to Check Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant. See Scheduled Maintenance on page 502. (A) Drain Plug (B) Filler Plug To get an accurate reading, the vehicle should be on a level surface. If the level is below the bottom of the filler plug hole, you will need to add some lubricant. Add enough lubricant to raise the level to the bottom of the filler plug hole. Use care not to overtighten the plug. What to Use Refer to the Maintenance Schedule to determine what kind of lubricant to use. See Recommended Fluids and Lubricants on page 511. 430