I had a diff failure on my Rickman about 4 years ago. I slowed for a speed hump on a private road, and there was no drive. Car was in gear ..... Hmm... I got out and looked underneath to see the prop turning merrily
After the AA collection I got home and jacked one side - turned the elevated road wheel and the prop turned. repeated with the other side and the same happened. When I removed the prop and diff I half expected there to be a few bits falling out, but it all looked good. With no real load on it the oil stiction must have been enough for things to turn as if normal when I tested it. I scoured the Country unsuccessfully, and then a very helpful Old Ford specialist directed me to a Rally restorer just 2 miles away from me, who I'd never known about. He promised a replacement the next day. Further inspection revealed all 6 ring gear retaining bolts were broken.during which time I'd ascertained the existing one could be fixed with some new (same as flywheel) bolts. I still bought the replacement as it would have been morally wrong to refuse the purchase. The Rally Specialist had never seen such a failure despite the huge BHP they put through their diffs!