Do I have to add a friction modifer in my fear diff on my 2007 F250, 6.0. I plan on using royal purple 75w-140? I have read conflicting posts. Anybody use arch oil in any of their differentials?
Can I use royal purple max at in my transfer case?
I recently purchased a 96 f250 7.3 4X4, i'm wanting to change all the fluids on it but wasn't sure what gear oil to use for the front differential? Could i use a gear oil which comes with a limited slip additive for the front, or is it strictly for the rear diff?