As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER TAKEOFF EICAS DISPLAYED LG AIR GRND FAIL AND LANDING GEARS WOULD NOT RETRACT. TROUBLESHOT USING FIM 32-63-00-810-802-A STEP 1 2 AND 14, FOUND NLG TO BE IMPROPERLY SERVICED. REPLACED FILLING PORT CHARGING VALVE ON NLG SERVICED NLG IAW AMM TASK 32-20-01-600-801-A.