As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SLOW OIL LEAK DEVELOPED ON REAR ACCESSORY CASE. FOUND OIL COMING FROM STARTER BETWEEN MOUNTING PLATE AND FRAME. REMOVED STARTER AND DISCOVERED OIL SEAL INSTALLED BACKWARDS. REPLACED STARTER WITH SERVICEABLE UNIT. REMIND MECHANIC'S GARLOCK SEALS SHOULD HAVE OPEN END FACING OIL PRESSURE.