belt probs

i have a problem with my belt and pulley setup. I have replaced the idler and tensioner pulley, as well as the power-steering pulley. The belt squeaks and squeals. It also ripped off a rib on the serpentine belt. before i replaced the power-steering pulley, it kept burning through belts. and it...

I just got a tranny rebuild,i drove it a few miles but after i stopped the truck and put it in reverse i heard a pop and the serpentine belt tensioner flew off.... Do they have to do anything with the serpentine belt when they remove/rebuild the transmission? thanx