what kind of gear oil for my diff?

[usa_ranger]

3.45 gear ratio . non LS
its a 1990 ranger, pretty sure same as 1990 1991 1992

would 75w90w be okay?

ive tried google searching for hours. tried calling multiple ford dealerships, not really getting good results.

 

[Hagan]

I have used 80w-90 viscosity gear oil in every Ford axle I have ever owned. I think that will be just fine though

 

[Pauls 4x4]

80w 90 like above and per the book. I don't bother with full synthetic on old things because I feel it leads to leaks.

 

[fr7]

I'm gonna put 80w 90 in mine , it came out of a 94 but I don't think it matters, mine calls for friction modifier since it's limited slip but you don't have to worry about that on yours, just use regular 80w 90, make sure your truck is in a level surface and make sure the fill plug will break loose BEFORE you loosen any bolts on the diff cover.