We have a Kubota LA525 and are major rookies when it comes to tractors. My husband was tilling, and he hit something (don't know what) and the PTO just stopped working. When he engages the PTO, he can't move forward when he lets off the clutch. We found twine wrapped around the wheel shaft and removed it, but other than that, we can't tell what is wrong. I have googled and and can only find when your PTO won't DISENGAGE, but mine won't engage. Thanks!