Diff Fluid Change with eaton posi

93gtmustang said:

I had an Eaton Posi.
I called eaton and they told me to use conventional 80w-90 gear oil, such as Valvoline.
They don't reccomend synthetic oil with there posi's because the clutch packs will not grip as well.
Go to a Ford dealership and get one 4 oz. bottle of friction modifier also.
They also said after you changer the fluid, to go to a vacant parking lot and do several figure 8's in one direction and then the same in the other direction, and this will get the fluid worked in and eliminate clutch chatter when you are driving.

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