2010 Chevrolet Suburban 2500 Owner's Manual - Page 489

What to Use Refer to the Maintenance Schedule to determine what kind of lubricant to use. See Recommended Fluids and Lubricants on page 7‑11. Headlamp Aiming The vehicle has a visual optical headlamp aiming system. The aim of the headlamps have been preset at the factory and should need no further adjustment. However, if the vehicle is damaged in a crash, the aim of the headlamps can be affected and adjustment can be necessary. All except 1500 Series A: Fill Plug B: Drain Plug . If oncoming vehicles flash their high beams at you, this can mean the vertical aim of your headlamps needs to be adjusted. When the differential is cold, add enough lubricant to raise the level from 0 (0 mm) to 1/8 inch (3.2 mm) below the filler plug hole. When the differential is at operating temperature (warm), add enough lubricant to raise the level to the bottom of the filler plug hole. . 6-55