So let's say that I've got Rotella synthetic in my tractor now and come time to change the oil again and I can't find Rotella synthetic around, is it ok to put something like Mobil 1 synthetic in? And TresCrows I have a L-4310, is that tractor conciderd a light tractor, like a B series? The whole reason I changed over to syn. oil is for the cold Maine winter starts, that made it worth it to me.