Welcome! Not familiar with this particular machine, but from what you're describing, I'd probably take a good look at the transmission freewheel release. On mine, engaging the release (so it can freewheel, and be pushed manually) pulls on a sheetmetal plate, which pushes a spring-loaded plunger into the transmission housing.

Disengage the release (to drive), and that spring-loaded plunger should pop itself out again. But if it's sticking, for instance, maybe the release is not actually disengaging. Disengaging my particular release doesn't actually "make" anything happen. It just moves the metal plate back, so the plunger can hopefully pop itself out again.

I'd take a good look at that. You could also jack up the back end, to get the wheels off the ground, start the engine, and see if they will even just turn weakly, when there is no resistance to them turning.

 

Welcome! Not familiar with this particular machine, but from what you're describing, I'd probably take a good look at the transmission freewheel release. On mine, engaging the release (so it can freewheel, and be pushed manually) pulls on a sheetmetal plate, which pushes a spring-loaded plunger into the transmission housing.

Disengage the release (to drive), and that spring-loaded plunger should pop itself out again. But if it's sticking, for instance, maybe the release is not actually disengaging. Disengaging my particular release doesn't actually "make" anything happen. It just moves the metal plate back, so the plunger can hopefully pop itself out again.

I'd take a good look at that. You could also jack up the back end, to get the wheels off the ground, start the engine, and see if they will even just turn weakly, when there is no resistance to them turning.
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Thanks for the reply.
I have the rear wheels off the ground (had to do this to move the machine). The wheels turn freely while off the ground (in opposite directions of course) but will not drive. There is a terrible noise when depressing the Forward or Reverse pedals and you can also feel it in the pedals. I'll stick a mirror under there tomorrow to try and see what's going on.