I’m having similar problems with a 2016 Pioneer 1000 that we bought new. My has had the clutch upgrade done to it already. A few months ago and just under 20,000 it quit driving. We were busy in our shop so I had someone take it to the little Mom & Pop Honda dealer and they replaced the shift motor. It worked great for a couple of months. Now with 20,100+ miles it grinds when you go to reverse and it doesn’t back up. The Honda dealer got shut down since last time. I’m not afraid to work on it now that I have a little time. I would just like some pointers as to what might be wrong and where to start. Thanks