oil pressure light on my 1030 came on after a few minutes running and won't go out. tractor has 1300 hrs. just changed oil/filter 10 hrs ago. found the sensor by the filter housing, removed the small bolt holding the electrical connection, disconnected it and ran engine and a small amount of oil came out through the bolt hole. Is this normal?. anyone know what size socket needed to remove the sending unit from block. My set only goes to 7/8-too samll, so have to go to town to buy bigger socket. do I need a special guage to check oil pressure and what should the pressure be thanks