What was found
AFTER TAKEOFF, THE NLG DID NOT RETRACT WHEN GEAR HANDLE WAS SELECTED UP. FLIGHT CREW FOLLOWING THE CHECKLIST THEN SELECTED THE GEAR HANDLE TO THE DOWN POSITION & RECEIVED 3 GREEN DOWN & LOCKED INDICATIONS. ACFT WAS DIVERTED WHERE AN UNEVENTFUL LANDING WAS ACCOMPLISHED. TECHNICIANS FOUND THE NLG UPPER BARREL NUT OVER TORQUED DURING TROUBLESHOOTING. THE UPPER BARREL NUT WAS PROPERLY TORQUED & GEAR SWING FUNCTIONAL CHECKS PERFORMED, NO DEFECTS NOTED. A SATISFACTORY MAINTENANCE CONFIDENCE FLIGHT WAS ACCOMPLISHED & ACFT WAS RETURNED TO SERVICE.