2007 Buick Rainier Owner's Manual - Page 402

All-Wheel Drive When to Check Lubricant It is not necessary to regularly check fluid unless you suspect there is a leak or you hear an unusual noise. A fluid loss could indicate a problem. Have it inspected and repaired. If the level is below the bottom of the filler plug hole, located on the transfer case, you'll 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 To determine what kind of lubricant to use, see Recommended Fluids and Lubricants on page 489. How to Check Lubricant To get an accurate reading, the vehicle should be on a level surface. Rear Axle When to Check Lubricant It is not necessary to regularly check rear axle fluid unless you suspect there is a leak or you hear an unusual noise. A fluid loss could indicate a problem. Have it inspected and repaired. 402