u/regiregir

I bought a John Deere tractor, model 1020S. It’s an old tractor, from around 1978. I have a problem. The PTO (cardan shaft) keeps spinning all the time and I can’t turn it off. The lever for the PTO is located between the two gear levers, and when I move it up and down, it doesn’t matter whether the tractor is in gear or not—the PTO still won’t stop.

I tried turning off the tractor and moving the lever into different positions, I started and stopped it, but it doesn’t matter—the PTO (cardan shaft) keeps rotating constantly. Even if I fully press the clutch, it still keeps turning. Has anyone had a similar issue? Does anyone know what the problem could be and how serious the fault might be?