What was found
AFTER TAKEOFF "GEAR DISAGREE" WARNING MESSAGE WAS DISPLAYED. RAN CHECKLIST, GEAR REMAINED DOWN WITH 3 GREEN LIGHTS. RETURNED TO DEPARTURE. LT MAIN WAS IN DISAGREEMENT. DURING TROUBLESHOOTING FOUND LT UPLOCK PROX TARGET LOOSE, RESECURED LT UPLOCK PROX TARGET IAW AMM 32-32. ALL CHECKS GOOD AT THIS TIME, CLEANED LT MLG WOW PROX SENSORS IAW AMM 32-61. ALL CHECKS GOOD AT THIS TIME. PERFORMED EXTENSION AND RETRACTION TEST IAW AMM 32-30, NO FAULTS NOTED AT THIS TIME.