I have a 1000, also. I'm trying to imagine what you mean by "the drive shaft locks up"
Can you give us some more information? Does the tractor not move or does it move when you put it in gear? If the shaft is locked up, it sounds like the tractor would not move. But you say you don't want to use it which sounds like it does move.
Does the engine continue to run but the drive shaft doesn't turn?
I suspect there is a rag joint or spirol pin issue... have you looked at the drive shaft to determine what is going on?
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