What was found
AFTER TAKEOFF AND SELECTING GEAR UP, NR 2 GEAR DID NOT PROPERLY RETRACT. RED "RIGHT", UNSAFE LIGHT, AMBER "R DOOR" AND AMBER GEAR SELECTOR HANDLE LIGHTS REMAINED ILLUMINATED. RAN CHECKLIST. CONFIGURATIONS WERE OK. CYCLED GEAR SOLVED PROBLEM. FA REPORTED LOUD NOISE FROM RIGHT SIDE PRIOR TO 2ND CYCLING OF THE GEAR. MAINTENANCE OPERATED GEAR USING GROUND CART. FOUND NR 2 GEAR RETRACT ACTUATOR LEAKING FROM PISTON SHAFT AND ACTUATOR SLOW TO STOW GEAR INTO UPLOCK. REPLACED NR 2 GEAR RETRACT ACTUATOR IAW Q400 TASK 32-31-11-000-801 AND 32-31-11-400-801. LEAK CHECK, BLEED NR 2 HYD SYSTEM AND FUNCTIONAL CHECK OF LANDING GEAR PRIMARY RETRACTION AND EXTENSION SYSTEM GOOD. AIRCRAFT RETURNED TO SERVICE.