BarryG

Out of curiosity has any kept track of the DEF usage in like miles per gallon? Since summer is in full swing I have been towing a lot more as many of you have I am sure. It sure seems like when towing I go through a lot of DEF. No doubt its usage increases while towing but just seems to be almost excessive and curious what others are seeing. I have not been keeping track yet but will be starting at next def fill which will be this week. I have a towing trip coming up in a couple weeks. Originally driving empty I think I was getting in the neighborhood of 800ish miles per gallon of def. Towing seems to drop that down to under 300 miles per gallon again I haven't really tracked it so not real sure on those numbers. I know the def tank is not linear on the gauge, sort of like the fuel tank. There is a gallon or gallon and a half before the gauge even begins to move (I read an article on it somewhere where it had been tested). In any case it seems regardless of towing weight it is high usage. Trailer one is a like an ATV trailer setup sort of like a stake bed with a piece of plywood across the front of it (using it to haul llamas it gives a wind break and as such has the aerodynamics of a brick) with a couple llamas in it it cant weigh more than 2000lbs. The other trailer is a 5th wheel that weighs in the neighborhood of 9k. It does seem to use more def as one would expect but even the light one sucks it down pretty good. This towing is in the mountains which may mean even more usage due to grades.
In any case anyone tracking their usage in miles per gallon would love to hear the numbers for comparison.

routerguy99

Towing my 5th Wheel with a 2015 RAM Def usage. From Salt Lake to Anaheim round trip I use 3/4 tank of Def. 1400 mile

iah145ca

We did a 2200 mile round trip towing our 8500 lb travel trailer. It used about 2 gallons of DEF.

Whitewolf

I'm getting about 1000 miles per gal of DEF. Since what I get is about the same as the others, I believe you have a problem.

SOhappy

Mine DEFinitely sucks is down while towing (refill every 2-3 tanks of diesel?). Empty my DEF gauge hardly budges (refill every 10 tanks of diesel?).