What was found
DISCREPANCY: AT 2300Z AT FL240 A LOUD NOISE WAS HEARD FOLLOWED BY THE ILLUMINATION OF THE NOSE GEAR RED LIGHT AND A VIBRATION AFTER THE NOSE GEAR AND MAIN LANDING GEAR GREEN AND RED LIGHT CAME ON. DECLARED AN EMERGENCY WITH MIAMI AND REQUESTED EMERGENCY VEHICLES. LANDED SAFELY, FIRE TRUCK INSPECTED, THE A/C TAXIED TO GATE. CORRECTIVE ACTION: PERFORMED INSPECTIONS OF ALL THREE LANDING GEAR IAW AMM 05-51-47 AND 32-13-00. FOUND MISSING BUSHING AT LEFT HAND OUTER AFT ATTACH BOLT. INSTALLED MISSING BUSHING IAW AMM 32-13-21. PERFORMED LANDING GEAR SENSOR INSPECTION AND TEST IAW AMM 32-09-00 AND 32-08-02, ALL NORMAL. PERFORMED LANDING GEAR LEVER SWITCH INSPECTION AND CHECK IAW AMM 32-61-11, NO DISCREPANCY NOTED, OPERATIONAL CHECK GOOD. PERFORMED GEAR EXTENSION AND RETRACTION ADJUSTMENT/TEST AND FREE FALL IAW AMM 32-32-00, 32-34-00, 32-35-00 ALL OPERATIONAL CHECKS NORMAL.