has any one when from dino oil to full synthetic oil & had better m p g & what oil & how much better m p g did you get ? i have 2011 chevy 2500 Duramax pulling 35 ft 5th wheel..
I use synthetic in everything from the the differentials to the engine grease in trailer wheel beings. The main reason is wear and high temperature tolerance. MPG is not a big concern other than winter where it is worth a a couple of MPG.