What was found
ENGINE SHUTDOWN AIR TURN BACK RAP FLT 7584, DISCREPANCY. 40 MILES OUT OF RAPID CITY, THE NR 2 ENG BEGAN LOSING OIL PRESS. THE CREW BEGAN TO RUN THE QRH & GOT A MASTER WARNING ON THE CASS. THE NR 2 ENG WAS SHUT DOWN & THE CREW HAD TO DO AN AIR TURN BACK TO RAP. AT THE TIME OF THE SHUT DOWN THE OIL PSI WAS 35 - 40 PSI. THE CREW DECLARED AN EMERGENCY WITH ATC. THE CREW HAD A NORMAL DESCENT & LANDED WITHOUT INCIDENT. MX FOUND THAT THE SOLENOID VLV ON THE OVER SPEED GOVERNOR WAS LEAKING ON THE NR 2 ENG. REPLACED THE OVER SPEED GOVERNOR.