Those with Eaton Posi Differentials....

[RacEoHolic330]

what type and weight gear oil are you using? Are you using fully synthetic? Also, what kind of friction modifier should I use. I'm installing the diff next weekend. Any help is appreciated.

 

[jerryD]

i'm just using plain 80-90w gear oil with a bottle of ford friction modifier.

 

[blown1989saleen]

yep, just dino based gear oil with a bottle of Ford friction modifier is all i used.

 

[hotrodnut]

According to Drive Train Specialties, if the Eaton is using the Carbon Fiber plates, then 80w90 petroleum oil without the friction modifier.

 

[cobra259]

Hotrodnut has it right:
The paperwork in the box that came with my Eaton diff, told me NOT to use synthetic fluid.

 

[RacEoHolic330]

So I shoudl use a non-synthetic fluid with friction modifier? What brands go you reccommend.

 

[Modular2v]

80 90 with motorcraft friction modifier...NO SYNTHETIC

 

[Modular2v]

castrol or valvoline

 

[RacEoHolic330]

thanks for the replies guys