As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED AT 11 PERCENT TORQUE A VIBRATION WAS FELT AND A CLUNK WAS HERD. INSPECTED MAIN ROTOR SYSTEM. LIFTED MAST AND FOUND .35 INCHES OF AXIAL PLAY. DISASSEMBLED MAST ASSEMBLY AND FOUND THE SPACER TUBE CRACKED IN (2) PLACES AND THE KEYS OF THE SPACER TUBE WORN. REPLACED SPACER TUBE, BEARING AND NUT IAW MFG.