Tractor Repair: ih 986 park shifter

Question
I just bought this 986. If you put it in park it will still roll on an incline, is there a park pin in tranny that is broke?

Answer
  When you move the lever into park, there is a linkage under the seat that moves a rod down through the top cover of the range transmission.  This rod moves a pawl that engages with a gear in the range transmission to put it in park.  Remove the seat and floor pan under the seat, and inspect the linkage for broken, loose, or bent parts.  Move the lever into and out of park and watch the linkage to make sure it is moving the rod up and down that goes into the transmission.  If everything looks OK, then possibly there is something wrong inside and the top cover will have to be removed to inspect the pawl and the gear.