What type of oil does a 1989 Chevy Truck rear end take?

A 1989 Chevy truck's rear end oil type depends on the specific rear axle it has. Chevrolet used several different rear axles in their trucks during that year. The recommended oil type will also vary based on the climate and the intended use of the truck.

To determine the correct oil, you must identify the rear axle code (usually found on a tag on the differential itself) or the axle ratio (found on the driver's side doorjamb sticker). Then, consult your owner's manual or a reliable repair manual specific to your truck's year, make, and model.

Without that information, I cannot give you a definitive answer. The oil could be a standard gear oil like 75W-90, 80W-90, or possibly a synthetic equivalent, but the exact specification is crucial to prevent damage. Using the wrong oil can lead to premature wear and failure of your rear differential.