Ok Guys I have been given the PDF for the new stant def caps.
It is hard to see, so I asked the Tech, if he could send a pic, he replied sure.
I also asked him what they were measuring and he said the inside of the cap (outside of the filler neck threads).
Elkhounds....the biggest worry i would have is the fuel more so than the DEF....yes...both are critical and worrisome...but the DEF repairs are a lot cheaper than fuel system....go for the locking fuel cap for now...the Stant 10510D i think is the number
Elks.....lol......can relate to you on the stocking of items...did the same on my truck last april and may...had a titan 65 gal tank for over a month waiting on truck to arrive....had gofia grill cover/screen, vent visors and hood deflector, bed tie downs for the holes in the bed rail...etc.....hope your truck arrives soon