Classic/Antique Car Repair: 1954 Chevy Bel Air Powerglide slippage, chevy bel air, 54 chevy

Question
My father left me his '54 Chevy Bel Air with Powerglide transmission. I live in the mountains of NC and, though the tranny fluid reads full, I'm feeling slippage on the hills when it gears down. Two questions: 1. what is causing the slippage/anything to be worried about? 2. what's a recommended transmission fluid for this transmission?

Answer
I am a Model A guy and those modern cars are not my expertise, but here is what I think:  The slippage is bad and you should do something about it.  The trans is quite simple and any trans guy could fix it easily.  If you are mechanical, you might try it.  At least take it out and take it to a shop that says they can fix it.  It's just planetary gears with some bands to adjust or replace.  A good trans shop can help you with the kind of fluid to use.  The other thing I recommend is to find a chevy car club and join it.  Even if it is not close to you.  They will know all about your car and be happy to help you enjoy it.  Just get about 10 or 15 of those chevy's going up and down those hills on a tour and you would have a lot of fun.  That's what car clubs do.
Good luck with it and have fun with it.
jack