As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING REPLACEMENT OF MODULE I MAG ASSEMBLY, DISCOVERED AN O-RING ON POWER SHAFT BETWEEN FREEWHEEL UNIT AND MAG SEALING RING HOLDER. THIS PARTICULAR MODEL ENGINE DOES NOT USE AN O-RING IN THIS LOCATION. THE PRESENCE OF THIS O-RING COULD RESTRICT SOME FLOW OF OIL TO THE FREEWHEEL UNIT. THIS COMPONENT WAS NEVER WORKED ON BEFORE THIS SEAL REPLACEMENT. DEFECT WAS PROBABLY DONE DURING ASSEMBLY BY MANUFACTURER.