Where is the oil filter located--I find fuel filter on left side and three other filters side by side on the right side-I think these three are hyd. filters--why 3 I do not know-maybe for three remote lines. If I can ever find the oil filter I plan to change the oil and use Rotella 15w40 or Delo400 15w40 oil --how much does it take..hadn't seen it in the operators manual . Thanks