What was found
ON DEPARTURE AFTER SELECTING GEAR UP, NLG REMAINED DOWN & LOCKED POSITION WITH GREEN MLG DOWN INDICATION. THE MLG RETRACTED NORMALLY. RECEIVED 2 EICAS MESSAGES ALONG WITH AURAL INDICATIONS FOR GEAR DISAGREE AS WLL AS NOSE DOOR OPEN. PLACED GEAR HANDLE BACK IN THE DOWN POSITION AND BOTH MAIN GEAR CAME DOWN AND LOCKED WITH A NORMAL THREE GREEN DOWN AND LOCKED INDICATION. BOTH EICAS MESSAGES EXTINGUISHED. RETURNED TO LAND UNEVENTFULLY. REMOVED NLG VALVE. INSTALLED NEW NLG VALVE, LEAK & OPS CHECK GOOD AT THIS TIME. WORK PERFORMED IAW AMM TASK 29-10-00-870-802,32-22-00-010-801-,32-22-00-710-801 AND 32-22-13-000-801.