2008 GMC Acadia Owner's Manual - Page 357

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 6-4. (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. 5-43