Bolens 38" 6 speed model 13AM 762 F 765. The pulley on the transmission loosend up and sheard the star shaped holders off of tractor. I tried to remove the 7/8" nut that hold the pulley on but the entire shaft spins so I am unable to remove the pulley. Is the fact that the shaft is spinning mean the Tranny is tore up inside? Appreciate any feedback I can get. Lawns getting pretty tall