I had a Centa unit go into the "horrible clanking" mode. It turned out that the nut which held the outer housing to the crankshaft had loosened. It sounded ok while under power but at idle, it was like a Ducati dry clutch on steroids. Fortunately, the crank splines are much harder then the Centa housing and a new, properly torqued, Centa unit cured the problem. It was painfully expensive as we were on the road at the time and had to resort to Uhaul rental to get the rig to the nearest dealer. I have the old Centa unit on the work bench with about 6,000 miles on it, the rubber rods look pristine. My present Centa has about 11,000 miles on it and I'm keeping my fingers crossed.