[swamp rat]

is it an automatic or standard tranny? I'm assuming automatic.

If you can make the screeching noise while stationary and reving the engine than yea probably the belts.

Loosing power on uphills and the rpm goes up: (Assumption that its an automatic)

You should be able to know if its not downshifting, if its not than the kickdown cable is not adjusted properly or there is an internal problem in the tranny.

check tranny fluid if an automatic, does it smell burnt? look black or dark brown? of it does than you may have a tranny problem.