What was found
(CAN) ENROUTE FROM TEL AVIV TO TORONTO AFTER THE LT SYSTEM WAS TOPPED OFF (IN TLV) LOSS OF HYDRAULIC FLUID OF THE L/H SYSTEM, THE A/C RE-ROUTED AND ASK FOR AN EMERGENCY LANDING. A/C LANDED SAFELY WITHOUT FURTHER INCIDENT. FOUND TO BE A LEAK AT THE DIFFERENTIAL INDICATOR PRESSURE DRAIN CASE MODULE FILTER (AROUND THE POP OUT). REPLACED THE PRESSURE CASE DRAIN FILTER MODULE DIFFERENTIAL PRESSURE INDICATOR.