Newer diesel trucks require something called DEF or Diesel Exhaust Fluid in addition to fuel. The name brand DEF costs about 12 bucks at Walmart and 20 bucks or more at gas stations. There is a generic brand called Super Tech that costs about half – so $6 for the same 2.5 gallons. I finallyContinue reading “Walmart diesel exhaust fluid (Super Tech)…why is it half price?”