I bought a John Deere 420 tractor and it initially ran well and everything worked. The PTO for the mower deck was intermittently not working. I am getting 12v with the switch on. I took it apart to further inspect it and it looks pretty chewed up. I can see the windings in a few spots. It is a older one wire clutch. Can I replace it with a two wire newer pto clutch or am I limited to a used one wire pto clutch? I reinstalled it and adjusted it with a .0018 feeler gauge and now it doesn't work at all.