Huh. Watching dad bush hog a little, he dropped a wheel over a hidden stump, started spinning. Going slow, in low 1. Hit the diff pedal, clunk-clunk-clunk -- not terribly loud, but there -- then nothing. Had to pull the diff pedal up manually. Now nothing. Just bought the tractor a month ago so I know little history other than it looks pretty good. What are the odds that someone has stripped the teeth on the diff lock? It's my understanding that you have to split the tractor in two to figure it out -- more of a job than I'm up to. Any thoughts would be much appreciated. Thanks fellas.