As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING AN INSP OF THE MAIN ROTOR MAST, FOUND LATERAL PLAY IN THE COLLECTOR GEAR. UPON REMOVAL OF THE MAST NUT THE LOWER MAST BEARING FELL OUT OF THE MAIN TRANSMISSION. UPON FURTHER INVESTIGATION FOUND DAMAGE ON THE LOWER BEARING FACE AND THE MAST NUT WHICH SHOW THE BEARING WAS ROTATING AGAINST THE NUT AND FOUND LATERAL PLAY IN THE COLLECTOR GEAR INSIDE THE MAIN TRANSMISSION.