1998 GMC Jimmy Owner's Manual - Page 290

Rear Axle When to Check and Change Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant when to change it. See and "Scheduled Maintenance Services" in the Index. How to Check Lubricant If the level is below the bottom of the fillerplug hole, you'll need to add some lubricant.Add enough lubricant to raise the level to the bottom of the fillerplug hole. What to Use Refer to the Maintenance Schedule to determine what kind of lubricant touse. See "Recommended Fluids and Lubricants" in the Index. 6-21