belt and motor pulley burnt up. Did not know the cause

Just tipped it back pulled the pulley off (the little plastic tits on the shaft just break off) the belt comes off easy. Carefully tap the new pulley on using a little grease or petroleum jelly on the splines before hand. The belt goes on easily when you slide the motor over. Just force the belt onto the big pulley just as you would on your car.
Problem was... the new belt and pulley burnt right up again when it tried to agitate after filling. So the motor was turning fine, and the pump shaft was turning fine, but the agitator (tranny) must have been locked up. Its pulley (the big one) would spin in one direction but was locked in the other when I checked it. Not knowing any better, I assumed that was normal. I still don't know if it is or not. That's the problem with these chat sessions...One guy says it should spin freely both ways another says it should be somewhat difficult to spin, you don't know if the control has to be set in a certain spot before checking. I gave up just going to buy another. This time a direct drive, although it doesn't make any difference there all junk.