Are your 3pt hitch arms up all the way? Looks like they are hitting the PTO shaft. If they are up all the way, move the pin in the vertical lift rod where it attaches to the bottom arm so that the bottom arm goes higher and clears the PTO shaft in tight turns. Some tractors you have to run it with the 3pt hitch arms down all the way when running PTO equipment to prevent damage.
At 4am I remembered that I didn't put the stabilizer pin in for the lift arm not in the pic.
It was more than likely the culprit. With the arms fully up, the tongue will hit the tire before the shaft hits the lift arms. That is, if I lock the lift arms in place.
I will probably do like Bulldog said and leave it off. It must have not spun very freely to have ripped it self apart. I don't hook it up with the tractor running and I don't go near a spinning PTO. So, a shaft cover does me no good. My daughters will sometimes drive it, but they have been taught to stay buckled up and not leave the cab unless it's on fire.
