2008 Chevrolet Corvette Owner's Manual - Page 325

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. If the level is below the bottom of the filler plug hole, you will need to add some lubricant. Add enough lubricant to raise the level to the bottom of the filler plug hole. What to Use To add lubricant when the level is low, use SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 89021677, in Canada 89021678) meeting GM Specification 9986115. To completely refill after draining, add Limited-Slip Axle Lubricant Additive (GM Part No. U.S. 1052358, in Canada 992694). See Recommended Fluids and Lubricants on page 6-11. Then fill to the bottom of the filler plug hole with the Synthetic Gear Lubricant. How to Check Lubricant Headlamp Aiming Headlamp aim has been preset at the factory and should need no further adjustment. However, if your vehicle is damaged in a crash, the headlamp aim may be affected. Aim adjustment to the low-beam headlamps may be necessary if oncoming drivers flash their high-beam headlamps at you (for vertical aim). To get an accurate reading, the vehicle should be on a level surface. If the headlamps need to be re-aimed, it is recommended that you take the vehicle to your dealer/retailer for service. 5-51