As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TRANSMISSION REMOVED AND SENT TO COMPONENT SHOP FOR 4,500 HOUR OVERHAUL. EXCESSIVE CORROSION WAS FOUND ON MAIN CASE UNDER INPUT QUILL FLANGE. ALSO, UNDER OIL JET. THIS IS THE FIRST TIME THESE AREAS HAVE BEEN DISASSEMBLED SINCE NEW AIRCRAFT WAS DELIVERED FROM B.H.T. CAUSE: MOISTURE PRESENT IN THE UNPROTECTED MAGNESIUM. RECOMMEND THESE AND OTHER AREAS BE PROTECTED BY PRIMER WHEN THE TRANSMISSION CASE IS NEW.