Update on my new Ram 3500

The first tank of DEF in my 2014 Chevy ran out pretty fast too. It threw me for a loop, having never had to deal with DEF before. We were traveling, trailer in tow. Found a GM dealer and they filled it up for me. They said, more than likely, when we purchased the truck, the selling dealer did not fill the DEF tank completely, although they should have. Made sense. Now, my usage is 5 gallons of DEF every 3000 miles. It's been very consistent since the first time "I" had it filled.

Second dealer also told us, we the truck idles a lot, it will burn up the DEF, thus skewing the mileage. Makes sense too.