What was found
AIR RETURN, AFTER TAKEOFF ON GEAR RETRACTION, GREEN HYD SYS WENT TO ZERO. ACFT ARRIVED AT GATE, FOUND BOTH MLG DOORS DOWN, AND LT MLG DOOR, HYD ACTUATOR, AFT FITTING SEPARATED FROM SWIVEL BODY AND LEAKING HYD FLUID. R & R GEAR DOOR SWIVEL FITTING IAW AMM 32-31-38. LEAK CHECKS GOOD.