My truck is a 1997 dodge ram 1500 slt. Magnum v-8 (360) auto w/ overdrive. 2 wheel drive with a limited slip differential I would like to know what kind of gear oil is supposed to be in the rear end and should it have an additive to make it more slick.

Differential Fluid (75W-90), GL-5. Add 8 oz. of Friction Modifier.

I recommend using Mobil 1 75W-90 Synthetic Gear Oil, adding 8 oz. of friction modifier, and changing it every 100,000 miles. This will improve performance, gas mileage, and protection.