Anyone know if the gear oil we have in our trucks from the factory is synthetic? Also is it a different weight in the front and back? I've been told that synthetic gear oil sometimes gets you better mileage. Was thinking about going amsoil.
They come from the factory with synthetic, not sure on the brand. As for weights 75W-90 in the front and 75W-140 in the rear, i just changed mine 2 weeks ago and honestly cant feel any huge difference besides piece of mind.