What was found
ON ARRIVAL AT THE ACFT GREEN HYD QTY WAS LOW, JUST ABOVE YELLOW RANGE MX SERVICED THE GREEN HYD BACK INTO TOP HAT MINIMUM. THEY STATED THERE WAS NO INDICATION OF A LEAK. DURING DESCENT WE HAD A LOW GREEN HYD QTY ALERT. THE OVHD QTY POINTER WAS AT RED DOT. WE TURNED OFF THE GREEN PUMPS AND LANDED W/O INCIDENT. AFTER MANUAL GEAR EXTENSION THE GREEN HYD QTY GAUGE INDICATOR MOVED TO THE 12 O'CLOCK POSITION. BY RETURN TO GATE IT DECREASED BACK ALMOST TO YELLOW AGAIN. REPAIRED CASE DRAIN HYD LINE IAW AMM 20-23-11. LEAK CHECKED GOOD.