As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 0117 - ONT - FLIGHT CREW REPORTED A LOUD BANGING NOISE ON GEAR RETRACTION WHILE CLIMBING. FLIGHT CREW RETURNED TO BLOCK. MAINTENANCE INSPECTED, REMOVED AND REPLACED NLG UPLOCK BOX PROXIMITY SWITCH AND PERFORMED A TEST FLIGHT. OPERATIONALLY CHECKED SATISFACTORY AND ACFT WAS RELEASED TO RETURN FOR SERVICE. (S)