I guess I have to put in my 2 cents to think about synthetic oil. Where I live(jackson WYO) it's essential. We have synthetic in all our vehicles in engines, difs, and TCs(Dodge Dump trk), JD Backhoe, Chev suburban, 2 mercedes diesels and 94 and 97 & 01 4X4 Dodge Cummins. When it hit -48 one...