What was found
DURING CLIMB, CREW RECEIVED A LG AIR/GND FAIL MESSAGE ON THE EICAS. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND A LEAKING O-RING ON THE NLG SERVICING PORT. THE O-RING WAS REPLACED, NLG WAS SERVICED, AND AN OPERATIONAL CHECK OF THE EXTENSION AND RETRACTION SYSTEM WAS PERFORMED. OPS CHECKED GOOD.