As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DISCOVERED AT ENGINE CHANGE, OIL COOLER BLOWER SPLINES WORN EXCESSIVELY. SUSPECT CAUSE - WHEN INSTALLED ON ENGINE, SPLINES WERE INSTALLED WITH GREASE. THE GREASE BLOCKED ENGINE OIL PASSAGE IN GEARBOX CAUSING LOSS OF LUBRICATION ON WET SPLINES.