As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT VACUUM PUMP LOOSENED FROM ENGINE AND CAUSED A LOOSE OF OIL PRESSURE. THE VACUUM PUMP DRIVE WAS DAMAGED IN THAT THE GEAR WAS ROUNDED OFF. IT WAS HARD TO DETERMINE IF THE GEAR WORE AND CREATED STRESS TO WORK IT LOOSE FROM THE ENGINE OR IT WORKED LOOSE AND THEN DAMAGED THE GEAR.