As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING 150-HOUR ZONE INSPECTION, FOUND APPROXIMATELY 2 INCH CRACK IN GEARBOX HOUSING NEAR INPUT SIDE. CRACK WAS NOT NEAR ANY MOUNTING BOSS, STUD OR HOLE. CRACK WAS ALMOST UNDETECTABLE BY VISUAL MEANS. MECHANIC FOUND CRACK BY WIPING CASE DOWN WITH SOLVENT AND THEN NOTICED OIL ON THE CASE THE NEXT DAY. FURTHER INVESTIGATION REVEALED THE CRACK.