TC Diesel
Well-Known Member
- Jul 14, 2016
- 2,489
- 711
- Truck Year
- 2015
More FCA / Deception Blame oil.... Hmmm Why are millions of other motors that have use 5/40 for billions of miles for decades NOT failing....When we build pulling motors we machine the tolerances to 20/50 or 50w whatever the customer prefers. The tolerance form 5/30 -5/40w .001 +/- 1-2 To my knowledge No production engine uses this spec, ALL are looe not tight so 5/40 would be the best oil in most cases ONLY extreme cold 0- temp would the viscosity make a difference, when warm the 5/40 would be better suited, 5/30 possibly add .25-.50PG better mileage in some conditions. Why are Owners Americans in general continue to be fooled by such shrew guesses of men. If they is FCA I would consider the info as worthless, deceptive and covering up the real cause.