I just installed a Eaton Truetrac limited slip in my 2008 F250 and am wondering about what kind of gear oil to use. I normally use the Amsoil Severe Gear 75W/140 but read somewhere on the board that you shouldn't use synthetic with the Truetrac. Conversely, I read in the owners manual that the Truetrac differential is designed to operate in those lubricants recommended by the vehicle/axle manufacturer for conventional differentials.
Does anyone have any insight into what kind of gear oil I need to use. I don't want to have issues nor take any risks ruining the new LSD.
I used Royal Purple in my Silverado when I installed my Truetrac. I used the gear weight recommended for the truck as found in the owner's manual. Can't remember right of hand what weight it was though. You might also find that it says not to use friction modifiers with it as well since it doesn't have clutches to wear out.