I have read alot on this on the web. I am no expert and have the same problem. It sounds like the transmission is out and is too expensive to replace...(time to buy a new one). The only other answer I got was to remove the center spindal down to the base( a greasy metal spindal). Then run a small amount of water on a cycle(w/o clothes) and see if the spindal turns.
If it does turn, then the teeth are probably worn out and it is cheap to replace the plastic spindal ( top agitator ). If not......... Maytag really needed to go out of business, everyone has the same problem....
Brian, October 2007