BlackSilverado

Mine was there from day 1, and most I've heard about were basically day 1 issues as well that just got worse over time, and/or it was missed during the test drive because they never got up to highway speed. If you can drive 75-80 and don't feel a shake, it's probably one of the many that dont have a problem.

Lift, wheels, and tires. Now I need some steps to get into it!

I have several friends and family with 2014-2018s and I'm the only one that has had vibration issues. Always test drive up to 75 mph and see if it shakes. One that does not shake will be smooth even on loud / rough surfaces, the ones that shake will feel awful even on the best pavement. Walk away from any that dont feel smooth as glass because there are plenty out there that ride great.

You might try giving GM customer care a call and start a case with them. Most likely they will get you a rental and throw parts at it until something fixes it or it doesn't get fixed, in which case they might do a buy back. I had to do it once and I got to trade it in for what I paid. Not quite a buy back, but at least I got out from it without any real financial hit.

I'm there with you, mine had the same problem and I spent a lot of time chasing it. All the techs would say is "feels like a tire balance issue". I will say that the lift definitely made the ride feel "tighter" if that makes sense, almost like the shocks are better, or whatever they did when modifying the truck ended up tightening up whatever was loose.

I havent checked my old shocks but I do have them in a box. I'll have to look and see if they were having issues.

I've been following this thread, as my 2016 midnight edition Z71 has had vibration issues since day 1. I had the driveshaft replaced, added a bed cover, rotated and rebalanced tires multiple times, got an alignment, tried adding weight to the bed, and basically had no improvement with any of these fixes. Vibration started around 70 mph and just got worse as I went faster. Probably the worst was around 74-78 mph, and it felt like the truck was going to rattle apart. The drive 35 hour drive to and from Colorado two weeks ago was AWFUL. I tried driving 75 mph just to not lose time, but it vibrated so bad I eventually slowed to 65-68 just so I didn't get shaken so bad. Now I might be crazy for spending money on a truck that has this bad of a vibration problem, but I had a 6" Pro Comp lift installed along with new wheels and 35" tires yesterday, and the vibration problem is totally gone. I don't mean it's better, it is 100% smooth as glass all the way to 80 mph, much smoother than even day 1 from the dealer lot. Just thought I'd throw this out there for anyone trying to find a fix. It's not cheap, and it's not really practical, but it did fix my issues.