As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON DISASSEMBLY AND INSPECTION OF PARTS, FOUND EXCESSIVE GALLING ON PINION GEAR AND SPALLING ON T/M GEAR. PINION GEAR HAD EXCESSIVE GALLING ON GEAR TEETH. POSSIBLY DUE TO IMPROPER MESHING OF GEARS. SECONDARY DAMAGE. T/M GEAR PN 689367. SN NN144843, TT: 849.6 HOURS. SPALLING GEAR TEETH.