Dolphin Deluxe 4 sometimes no drive, sometimes no impeller

by Phil
(Northern NJ)

So my Dolphin Deluxe 4 is several years old, probably at least 6, and recently it has started to show it. I have changed both of the tracks, the climbing wheels, and now all 6 bearings. The impeller fan looks good, no damage, and the drive nut gap was slightly widened, so I tightened that back up with a bench vise. My problem is now it sometimes will not move the tracks, and sits in one place throwing water up, the impeller working beautifully. Other times the tracks are running, but the impeller is not. I am flummoxed!