As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FORWARD COUPLING BECAME DISLODGED FROM PLATE AND WORE HOLES THROUGH THE PLATE. THIS ALSO CAUSED DAMAGE TO THE TRANSMISSION FLANGE NUT PN 206-040-047-001. SHOP TEARDOWN REVEALED ONE END OF THE SPRING HAD BROKEN OFF CAUSING THE SPRING TO SHIFT.