I have a 2016 ram 2500 6.4 auto with 4.10's that I ordered new. I noticed that when I rotated the tires at 8k and was right around the same time I first used the fwd I started to feel this vibe in the floorboard. Brought it to the dealer and they balanced the tires of course, have to start somewhere and it did seem to change it. It was between 60-80, come and go but now it seems to be around 70mph. It's not rpm related, it's not the mds since I can put it in tow mode and it's still there. The last time I had a vibration like this it was a driveshaft. Of course I coated the underside of my truck with fluid film and painted the driveshafts with POR15. Going back in on Tuesday so they can swap out a set of tires from a new truck then the rear shaft to see if it makes a difference since I'm the only one that can feel it. I'm waiting for them to blame the pain on the shaft. Anyone else have this?