What was found
AFTER TAKEOFF AND CLIMBOUT FROM SAL RT ENGINE FILTER CLOGGED LIGHT ILLUMINATED, AC DIVERTED TO GUATEMALA. UPON PARKING MAINTENANCE REMOVED THE MAIN OIL FILTER ASSY AND INSPECTED FOR FOD, NONE WAS FOUND. MAINTENANCE REPLACED THE RT ENG MAIN OIL FILTER PER MD 80 AMM 79-20-06 AND 79-35-01 AND DETERMINED THE ENGINE DIFFERENTIAL OIL PRESSURE INDICATION SYSTEM WAS AT FAULT. MOC ISSUED DMI M79JN-4632 AC WAS RELEASED PER MEL 79-5. AC 836RA REPOSITIONED TO IWA, UPON ARRIVAL RT ENGINE DIFFERENTIAL OIL PRESS SWITCH WAS REPLACED PER MD 80 AMM 79-35-01 DMI WAS CLEARED. AC OPERATIONS WERE CONDUCTED 6/29/2011 NO FURTHER CREW REPORTS WERE RECEIVED AT THIS TIME.