What was found
AIRCRAFT WAS GROUNDED: CLIMBING THROUGH FL240 FELT A VERY SMALL THUMP ON FEET, MOMENTSLATER NOSE GEAR UNLOCK LIGHT AND L/G GEAR NOT UNLOCKED ECAM. SUSPECT GEAR UP LOCK ALLOWED GEAR TO FALL AND REST ON DOORS, GEARDOORS INDICATE CLOSED. GEAR LOWERED NORMALLY, RETURNED TO DFW AND LANDED UNEVENTFULLY. MAINTENANCE REPLACED NLG UPLOCK ASSY PER AMM 32-31-21-400-001-A.