As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE BOLT SECURING THE FORWARD U-JOINT ONTO THE DRIVESHAFT HAD BACKED ALL THE WAY OUT. THE BOLT SECURING THE AFT U-JOINT TO THE DRIVESHAFT WAS LOOSE EVEN WITH THE LOCKING TAB WASHER INSTALLED. UPON INVESTIGATION, IT APPEARED THE WRONG LOCKING TAB WAS USED DURING OVERHAUL.