Man.. I just noticed my DEF level. One thing I notice now is that this 23' burns way more DEF than any of my previous trucks. Ive had them all 20' 21' 22'. I only have 1800 miles on this truck and Ive now been through 5 gallons of DEF. (Ive only pull my 5th wheel on 1 trip 200 miles up and 200 back.)