This almost seems like an epidemic on the Torrington bearings as of late. I had to replace two of them in my Voyagers, all within the past two or three weeks and, had I not been in the company of a more experienced individual, I might have still been trouble-shooting this problem.
I had crashed one of my Voyagers about three weeks ago. On the first flight attempt after the rebuild, the engine RPM would respond, however the main rotor and tail rotor would only turn very slowly. Since I had not been able to secure the engine after the crash until I could pull off a fuel line, I figured that the clutch was history. After tear-down, both the clutch and clutch lining were both fine and ther was no evidence of cracking in either the clutch bell or clutch itself.
A flying buddy came down to fly and visit the following Friday and I was telling him about the problem and he immediately told me that it was the one-way or Torrington bearing in the auto-rotation clutch...somthing I had not seen or experienced before. On close examination, we found two hairline cracks in the outer case of the bearing.
Something to file away for the future.
"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105