As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE WAS REMOVED FROM AIRCRAFT BECAUSE IT WAS GENERATING METAL IN THE OIL. AFTER DISASSEMBLY, IT WAS VIEWED THAT THE GEAR SHAFT IN QUESTION HAD SHEARED. THE SHAFT HAD SHEARED FROM WHERE IT MATES WITH THE MAIN GEAR PORTION OF THE PART. NO PROBLEMS WITH RELATED GEARS, BEARINGS, ETC., WERE FOUND TO SUBSTANTIATE A CAUSE FOR THE FAILURE. PART WAS RETURNED TO ALLISON FOR FAILURE ANALYSIS PER ALLISON REF CN0099F-REH 0200. (X)