Rebuilding 2 Eaton truck differentials and I am wondering if it is OK to run 75w-140 in an axle assy that calls for 75w-90? Both oils that I have are synthetic Amsoil, I just don't have enough of each to do both axles. I'm asking if it is OK to run 75w-90 in one axle/diff and 75w-140 in the other axle/diff. If it is OK, does it matter if the front or rear gets the 140?
The super high horse heavy haulers run the heavier oil.The rear diff dose most of the work. In cold temps I would switch back.
I run in colder climates but am always 70K-86K and only run in the Rockies, where I am working them a bit.