What was found
DFW - FLT 1736 - AFTER TAKEOFF STL, WHEN LANDING GEAR RETRACTED, NOSE LANDING GEAR INDICATED UNSAFE. RECYCLED LANDING GEAR AND GEARS RETRACTED WITH NORMAL INDICATIONS. AIRCRAFT PROCEEDED TO DFW AND LANDED WITHOUT INCIDENT. REPLACED NOSE LANDING GEAR DOOR SELECTOR VALVE FILTER. ACCOMPLISHED NOSE LANDING GEAR RETRACTION CHECK WITH NO DEFECTS FOUND. SYSTEM LEAK AND GROUND CHECKED NORMAL OPERATION. (M)