What was found
ON FLIGHT 3664 AFTER TAKEOFF THE DFW TOWER INFORMED THE FLIGHT CREW AS WELL AS MAINTENANCE OPERATIONS CONTROL THAT A LARGE AMOUNT OF FLUID OR SMOKE WAS COMING FROM THE RIGHT WING. THE CREW DECLARED AN EMERGENCY AND RETURNED TO FIELD. THE AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. DETERMINED THE FLUID OR SMOKE ISSUE WAS CAUSED BY VENTING HYDRAULIC FLUID. NR 2 SIDE-BALANCED HYDRAULIC NR 1 AND NR 2 IAW ETN-EM-29-017. REMOVED AND INSTALLED NR 1 AND NR 4 BRAKE SHUTTLE VALVES IAW 32-49-03. NO LEAKS NOTED. OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.