As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PRE-FLIGHT, PILOT FELT A ROUGH CLUNK IN THE ROTOR SYSTEM. AS THE ROTOR WAS TURNED, SUBSEQUENT INSPECTION FOUND THE GEAR OIL PUMP OF THE MAIN ROTOR TRANSMISSION REQUIRED A VERY HIGH BREAK-AWAY TORQUE TO BEGIN ROTATION AND AFTER THAT, IT WAS RATCHETY. UNIT REMOVED AND SENT IN FOR OVERHAUL.