As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) CENTER PLUG LEAKING OIL INTO CAVITY BETWEEN FREE WHEELING UNIT AND INPUT DRIVESHAFT FLANGES. OIL THEN TRANSFERRING INTO DRIVESHAFT COUPLING VIA VENT HOLE IN COUPLING CAP. GREASE IN COUPLING IS DILUTED BY OIL CAUSING GREASE LEAKAGE.