What was found
UNSCHEDULED LANDING UNDER AMBER ALERT DUE TO A RED GEAR LIGHT INDICATION. FLIGHT CREW REPORTED AFTER TAKEOFF, AT LANDING GEAR RETRACTION WITH GEAR HANDLE IN OFF POSITION HAD RIGHT MAIN GEAR RED UNSAFE LIGHT INDICATION. DURING TROUBLESHOOTING FOUND RIGHT GEAR DID NOT FULLY RETRACT AND STOPS SEVERAL INCHES SHORT OF BEING FULLY UP, THEN MOVES SLOWLY UPWARD AND MUST BE MANUALLY PUSHED TO FULL UP POSITION. WITH GEAR FULLY UP, ALL COCKPIT GEAR INDICATIONS WERE NORMAL. REMOVED AND REPLACED RIGHT MAIN LANDING GEAR RETRACT ACTUATOR ASSEMBLY. ACTUATOR FAILED THE INTERNAL LEAKAGE TEST AND APPEARS TO BE BYPASSING THE PISTON SEALS.