Going to do some differential PM this summer in both F150s. Historically I would just run Motorcraft synthetic and not worry about it, but the Eaton posi in my 2011 9.75 is a really chatterbug and got it almost smoothed out with Amsoil SVG and a double shot of their FM. Now, I typically run a budget synthetic in the fronts as they see very limited use so that’s no worry there.
2011: stick with what’s working Amsoil 75w140 and maybe add FM if needed after or keep it simple and run Synpower from the local shop? When I installed the posi it went well but my bearing load was on the tight side of spec (40k miles ago)…
2018: this one is pretty simple, all factory with factory e-locker. Any reason to pay extra for the Amsoil? I figure any decent 75w140 will be totally adequate…
2011: stick with what’s working Amsoil 75w140 and maybe add FM if needed after or keep it simple and run Synpower from the local shop? When I installed the posi it went well but my bearing load was on the tight side of spec (40k miles ago)…
2018: this one is pretty simple, all factory with factory e-locker. Any reason to pay extra for the Amsoil? I figure any decent 75w140 will be totally adequate…