I was just outside plowing and the tranny stuck in low gear. (and 4WD) The shifter linkage flops forward and back but doesn't grab anything. I followed it back to the gearbox and an not sure if it is a key way or something else. Any direction would be appreciated.

 

if its still hooked on w/ the linkage then it come apart inside the tranny, maybe shifting fork, pin broke??

 

You can take the cover off where the shift linkage goes into the trans. Its pretty easy, but there are some springs and detents in there. My guess would be the problem is in there.