What was found
DURING PREFLIGHT INSPECTION, PILOT NOTED THE TAIL ROTOR BALANCE WHEEL HAD SLIGHT ROTATIONAL MOVEMENT. MAINTENANCE WAS DISPATCHED TO INSPECT THE TAIL ROTOR ATTACHMENT. TAIL ROTOR RETENTION NUT 109-0130-85-1 WAS LOOSE CAUSING SLIGHT WEAR TO THE TAIL ROTOR GEARBOX OUTPUT SHAFT(SPLINES) AND TRUNNION 109-8131-33-101 SERIAL NUMBER M127. REPLACED TAIL ROTOR GEARBOX 109-0440-01-119 SERIAL NUMBER H103596 TSO 2520.2 TSI 376.0. REPLACED TRUNNION 109-8131-33-101 SERIAL NUMBER M127 TSN 644.8. REPLACED TAIL ROTOR RETENTION NUT 109-0130-85-1. REPLACED SLIDER SLEEVE 109-0130-90-117 SERIAL NUMBER A2-0327 TSN 112.4. THE SLIDER SLEEVE SHOWS ABNORMAL WEAR AT THE AREA THE SLIDER SLEEVE MATES WITH THE TAIL ROTOR GEARBOX OUTPUT SHAFT.