Originally Posted by Greg S
8.5 hauling a 40' trailer with 2 cars and loads of heavy tools in it. Averaging about 65-70 MPH. Really seemed to suck up the DEF with the big load on it.
DEF usage is a ratio to fuel usage.
Use more fuel, it will use more def
Should be somewhere close to 1.5 gallons on DEF per 100 gallons of fuel.