You get 10k miles out of a 2.5 gallon container of def?I dump in a 2.5 appx every 10K miles from Wally World. About 10 bucks... a total non issue.... And a great oil change container!
Really? Are you sure?
We have 5 of the baby dmax's in a group here at work and all of use get around 1k miles per gallon of def when empty. Towing they use significantly more (8.2 gallons during my last 1500 mile trip pulling 5k lbs).
GM also states the 1k per gallon number as an estimate.