What type of rear differential oil do you use for 2004 Chevy silverado?

The type of rear differential oil for a 2004 Chevy Silverado depends on the axle ratio and whether it has a limited-slip differential. You must check your owner's manual or the sticker on the differential cover for the correct specifications. The sticker will usually indicate the recommended oil type and capacity.

However, generally speaking, for a 2004 Silverado, you'll likely need either:

* 75W-90 gear oil: This is a common viscosity for rear differentials. If your owner's manual doesn't specify otherwise, this is a good starting point. Look for gear oil that meets API GL-5 specifications. GL-5 oils are designed for hypoid gears, which are typically used in rear differentials.

* 75W-140 gear oil: In hotter climates or with heavier towing, a 75W-140 gear oil might be recommended. Again, check your manual first.

* Limited-Slip Additive: If you have a limited-slip differential (LSD), you will need a gear oil specifically formulated for limited-slip differentials or you may need to add a friction modifier additive to a standard GL-5 gear oil. This is crucial to prevent premature wear and failure of the limited-slip components. The owner's manual or differential sticker should tell you if you have an LSD.

Do not rely solely on this information. Always check your owner's manual for the exact specifications recommended by Chevrolet for your particular 2004 Silverado model and axle configuration. Using the incorrect oil can severely damage your differential.