What was found
AT ALTITUDE, HEARD A GRINDING NOISE WHICH LASTED FOR ABOUT 5 SECONDS COMING FROM BACK OF AIRPLANE. WAS FOLLOWED WITH A LT, HYD PUMP, FAIL, CASS MESSAGE. PULLED UP SCHEMATIC & COULD SEE THE FLUID WAS DRAINING FROM LT HYDC SYS WHEN FLUID REACHED 0 GOT A AMBER LT HYDC PRESS LOW CAS MESSAGE. DECLARED AN EMERGENCY, MANUALLY EXTEND THE GEAR, PERFORMED EDHP OPERATED DRY INSPECTION CHECK, NOTED BRONZE & STEEL IN BOTH THE CASE DRAIN & PRESSURE FILTERS. REMOVED LT EDHP DUE TO SHAFT SHEARED. INSTALL NEW. PERFORMED LEAK CHECK, BLEEDING OF LT HYD SYS, NO DEFECTS NOTED. IAW AMM 29-12-01, 29-10-00 AND 12-12-00.