Amsoil 75W-140

[mobilnissan1991]

put in some Amsoil 75W140 in the 8.8 rear diff in my ‘12 F150 at 203k miles, currently has 283k so 80k on the oil. How long can I safely go? I tow light loads on occasion, and daily I have anywhere from 200-1000 lbs in the bed for work. I drove mostly interstate miles. Wasnt sure if I should dump it now or wait till 303k

Ill go with either HPL or Redline 75W140 this time coming.

 

[drtyler]

100k miles should be fine. I have done it several times with the same gear oil (Amsoil Severe Gear 75W-140).

 

[burbguy82]

@mobilnissan1991
I do 50k normal usage........at least that is what I done in the past. But I over do things and enjoy the process. I also dont suck the stuff out either.......I remove the cover clean out the pumpkin, and magnet etc.

Amsoil is a good oil of course, so I doubt you have done any damage, and are likely well within the life of the fluid, assuming the diff is good. All those highway miles allow the diff to get hot, and burn out any water, and highway miles do nothing for wear really........so IMO you are good.

Why change? My not go with Amsoil again? The squeeze bottles are legit. I recently used some 75w110......might consider that viscosity.....not sure what your calls for, but they are all made by the same folks.

 

[dnewton3]

Assuming you don't get water intrusion (fording streams, etc), then diff fluids such as the premium stuff (Amsoil SG, HPL, RL, etc) are probably good to 100k easily after break-in has occurred.

Of course, a UOA can actually help you make these decisions ....