What was found
AFTER TAKEOFF, FAILED TO RECEIVE A GEAR UP INDICATION ON THE RT MAIN. WE CYCLED THE GEAR 3 TIMES WITH NO CHANGE. DUMPED FUEL AND RETURNED TO DEPARTURE, LANDING UNDER MAX WEIGHT. DISCOVERED SOME ICE IN THE AFT FLANGE OF THE GEAR DOOR THAT MAKES CONTACT WITH THE FUSELAGE. SUSPECT IT WAS A RESULT OF SERVICING OUR WATER IN BELOW FREEZING TEMPERATURES. MAINTENANCE PERFORMED A GEAR SWING AND NO DEFECTS WERE NOTED. DEPARTED WITH NO FURTHER ISSUES.