As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEARBOX WAS RETURNED FOR 'METAL CONTAMINATION'. AFTER TEAR DOWN OF GEARBOX, NOTICED TABS WERE BROKEN OFF TAB WASHER (ITEM 20A OF SEI 663) AND RETAINING NUT (ITEM 25 OF SEI 663) WAS BACKED OFF THREAD ON PROP SHAFT (ITEM 80 OF SEI 663). NOTE: NO OTHER DAMAGE SEEN. REF: CMM 72-11-02.