As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT DETECTED A HUM AND VIBRATION FOR APPROXIMATELY ONE MINUTE. FOLLOWED BY A BANG AND LOSS OF POWER ON #2 ENGINE. FOUND #2 FLEX COUPLING AT THE TRANSMISSION DESTROYED. SCRAPPED COUPLING AND REPLACED WITH SERVICEABLE PART--RETURNED AIRCRAFT TO SERVICE.