As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A LANDING GEAR RETRACTION CHECK THE L/H LANDING GEAR WHENT FROM THE UP POSITION TO THE DOWN AND LOCK POSITION BY OT SELF. AFTER FURTHER INVESTIGATION FOUND THA THE L/H ACTUATOR SHAFT NUT HAD FAILED AND COMPLETLY CAME OF THE SHAFT, CAUSING THE LANDING GEAR TO DROP TO THE DOWN AND LOCK POSITION.