What was found
(CAN) DURING FLIGHT THE CREW OBSERVED TORQUE PRESSURE FLUCTUATION ON #1 ENGINE. SUBSEQUENT ENGINE OIL PRESSURE FLUCTUATIOINS LED TO THE #1 ENGINE BEING SHUT DOWN. POST FLIGHT INSPECTION FOUND THE PROBLEM WAS A LEAKING PROP SHAFT SEAL. THE SYSTEM WAS SERVICED AND THE ENGINE AND PROP WERE PREHEATED. NO LEAKS WERE EVIDENT ON A GROUND RUNUP AND THERE WAS NO CONTAMINATION IN THE ENGINE SCREENS. THE PROPELLER SEAL WAS REPLACED.