1999 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 323

yellowblue Rear Axle When to Check Lubricant Refer to the Maintenance Schedule to determine how often to check the lubricant. See "Scheduled Maintenance Services" in the Index. The proper level for the 1500 Series is from 5/8 inch to 1 5/8 inch (15 mm to 40 mm) below the filler plug. The proper level for the 2500 Series is from 0 to 3/8 inch (0 to 10 mm) below the filler plug. Add only enough fluid to reach the proper level. What to Use Refer to the Maintenance Schedule to determine what kind of lubricant to use. See "Recommended Fluids and Lubricants" in the Index. How to Check Lubricant Four-Wheel Drive Most lubricant checks in this section also apply to four-wheel-drive vehicles. However, they have two additional systems that need lubrication. 1500 Series shown, 2500 Series similar 6-25