I have a 1986 ford with the C6 tranny on a motorhome what fluid does it take?

It looks like from what I was reading that type F is what will work but then I ran across info that states its only used in c6's from the 70's. Am I ok using type F? Also this vehicle is new to me is there anyway to tell what fluid type is in it now?

I would use the today's commonly produced general Mercon/Dexron III ATF. It's much better than the Type F and in the '80s, Ford was using Mercon for a while.