I don't know for sure that the DEF was full. The gauge "said" full and the dealer "said" they filled it so I don't know what happened but it was bad. From Milwaukee to just about all the way to St Louis I was straight into a 25 mph to 30 mph wind so that may have had something to do with it. I'm new to this DEF stuff, I guess with time I'll get figured out.
Now today after arriving in Holbrook AZ, I refilled the DEF, the gauge "said" I was down to a quarter tank, I think that's right because I filled it at the TA just west of town on I 40 and it took 4 gallons. We had really bad winds today all the way from Bristow OK to here (Holbrook), we burned A LOT of diesel too. I kept the rig moving between 65 mph and 72 mph. We went through about a tank and a half of diesel. The power of this truck is amazing, especially up the grades, in the wind. Hard to get the grin off my face! :B
BTW, the factory air ride is sooo sweet, very smooth ride with the trailer on, that is another amazing feature of this truck.
Dan