Ody has 205K on it. Trans failed to backup one day. Also seemed to move forward in higher gear. When shifted to reverse, it makes noise similar to grinding and does not reverse at all. I replaced or cleaned all the screens on the solenoid shift valves on top and on front. New gaskets and o-rings. Replaced inline filter also. Drained and refilled trans with Honda fluid. Now trans drives normal, shifts forward normal, but same noise and no reverse. On a hunch I drove up a hill that had a turnoff below me and let it coast backwards in reverse. What do you know, reverse is operational. I can continue to reverse for blocks, under power, even uphill. Soon as out of reverse, either to park or neutral, then back to reverse, just grinds. Still drives forward normal. Can repeat coasting in reverse over and over, always works till shift out of reverse, then fails. Any thoughts?