What was found
FLIGHT 3776, CREW REPORTED THAT DURING APPROACH, WHEN GEAR LEVER MOVED TO THE DOWN POSTION, NOTHING HAPPENDED AND RECEIVED A GEAR DISAGREE MESSAGE. NO WIND NOISE FROM NOSE AREA OR INDICATION ON ED1. EXAMINED THE HYDRAULIC SYNOPTIC PAGE AND ALL SYSTEM RESERVOIRS AND PUMPS WERE INDICATING NORMAL. RECYCLED GEAR WITH NO CHANGE. BROKE OFF APPROACH AND DECLARED AN EMERGENCY. RAN ALL APPROPRIATE EMERGENCY CHECK LISTS. MLG CAME DOWN USING MANUAL RELEASE SYSTEM. RETURNED FOR AN UNEVENTFUL LANDING. AIRCRAFT REMOVED FROM SERVICE. REMOVED AND REPLACED LANDING GEAR SELECTOR VALVE IAW AMM 32-32-10. PERFORMED EXTENSION / RETRACTION IAW AMM 32-30-00. PERFORMED OPS CHECK OF NOSE WHEEL STEERING IAW AMM 32-51-00. OPS CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.