what type trans fluid is everyone using

Changing the fluid, no matter what type you use, probably isn't going to help if there's slipping going on. These transmissions are simple enough in design that if there is a slipping problem it's most likely a friction material problem(wear) or leaking piston seal etc. Unfortunately changing the fluid now may make it worse. But if it does you come to the same conclusion anyway. Time to rebuild it.
If I were to go ahead & change it(who knows, you may get lucky) I'd use either Dexron or type F. You don't want to put a high dollar fluid in it just to drain it out & throw it away if it doesn't help.