I have the Ford 6.7. I've towed with the truck about 3500 miles and just now had to add DEF for the first time. My hauler bed has the DEF filler in the cabinet that's across the top of the driver's side rear tires. I bought a jug of DEF at a fuel stop this week then again a couple days ago.
Went to use the first jug and no filler nozzle
Opened up the box for the Blue DEF brand and it had a filler nozzle. Thank you Blue DEF. Added a whole jug (couple gallons?). Then used that nozzle on the first jug and added all but about a quart of it. Poured the remaining DEF into the Blue DEF just as it's lower/squattier and it fits in my cabinet better.
Interesting note, I wanted to use DEF "at the pump" at the Flying J here in Gillette. Went to the diesel lanes, saw the "DEF at the Pump" signs near the pumps. Guess what? No DEF at the pumps there yet. Jeez, give me some spray paint - I'll fix your signs for you
So, I've yet to "pump" any DEF into my tank, just jug dumping for now.