Hey guys.
I have a 2015 Regular cab 2wd V8 with 12k miles, i too, had the dreaded vibrations, they were so bad that i couldn't put anything on my center console (bottles would rattle all around, and my cellphone or anything else would even jump out of the console).
My dealer aligned the truck, balanced it, with no success.
Anyways, i recently installed a set of Fox 2.0 shocks to level the truck, and guess what? vibration is gone, completely GONE. i think at this point it might have had something to do with the pinion angle or driveshaft.
Not saying everyone to go out and change shocks, but it's what fixed it for me.