2001 GMC Safari Owner's Manual - Page 276

All-Wheel Drive (If Equipped) If you have an all-wheel-drive vehicle, be sure to perform the lubricant checks described in this section. However, they have 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 "Periodic Maintenance Inspections" in the Index. If the level is below the bottom of the filler plug hole, you'll need to add some lubricant. Add enough lubricant to raise the level to the bottom of the filler plug hole. What to Use Refer to the Maintenance Schedule to determine what kind of lubricant to use. See "Recommended Fluids and Lubricants" in the Index. 6-24