What was found
EN ROUTE PHX-DTW, THE RIGHT HYDRAULIC SYSTEM OVERHEATED. THE RIGHT HYDRAULIC PUMP WAS DEACTIVATED. RIGHT SYSTEM PRESSURE WAS NORMAL FOR APPROXIMATELY 15 MINUTES THEN THE RIGHT SYSTEM QUANTITY SLOWLY DECREASED TO ZERO. THE FLIGHT DIVERTED TO MKE AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE RIGHT ENGINE DRIVEN HYDRAULIC PUMP AND ITS ASSOCIATED FILTERS. SYSTEM TESTS WERE SATISFACTORY.