What was found
(CAN) ON MAINTENANCE FLIGHT WHILE DOING AN ALTERNATE GEAR EXTENSION AND THE NR 2 HYDRAULIC SYSTEM WAS AT ZERO PRESSURE. TO CLOSE GEAR DOORS POWER TRANSFER UNIT WAS TURNED ON TO RE-PRESSURIZE NR 2 SYSTEM. OK FOR A COUPLE OF SECONDS, THEN INDICATING LOST. DOORS STAYED OPEN. NR 2 ENGINE HAD BEEN SHUTDOWN ALSO AS PART OF PROCEDURE, IT WAS RESTARTED. NR 2 HYDRAULIC PRESSURE STILL AT ZERO AND QUANTITY STARTED TO FALL OFF. FOUR CAUTION LIGHTS ON. NR 2 ENGINE HYDRAULIC PUMP, NR 1 DC GENERATOR, ROLL SPOILER HYDRAULIC, AND NOSE STEERING. NR 1 GENERATOR FELL OFF-LINE AND WOULD NOT RESET. NR 2 ENGINE SHUT DOWN AGAIN TO STOP ANY FURTHER PROBLEMS WITH NR 2 HYDRAULIC SYSTEM. EMERGENGY DECLARED AND ACFT LANDED OK.