I am trying out Rotella 15-40 this oil change... At the end of the oil's life around 2000miles on 10-30 Castrol GTX High Mileage or Mystic Syn Blend, I would start losing oil pressure. If the engine is good and hot and esp when I am offroading at low RPM, the oil pressure will drop low enough for the beeper to go off. Probably not a good sign, but as long as the oil is good and fresh, the pressure holds fine.
Is there an AMSOil equivalent to MT90? I have a great source for AMSOil but not Redline.