Mitch:

You'd have to open up the gear-case and see how the shaft is attached to the gear inside.

If its just a setscrew, you've got a very easy fix. Just make sure to lock-tite it when you replace it on the new shaft.

If its pressed in, not so easy, but do-able at a machine shop for a few bucks (or perhaps a HS or college class-shop for nada)

If its pinned... well, you have to put a pin-drive on the new shaft too, meaning drilling the steel rod.

Got any way to show the scale of those beasts?

WhiteWolf