I am now another added to the long list of those having this issue. First bought a used 2014 LT all black with 9k miles on it and it drove super smooth. Then I made a horrible choice to trade it for another 14 that was identical but it was Red and only had 3k mile on it and was at a great price... Big mistake, on the test drive it drove pretty good but I never got it up on the freeway..also another big mistake because on the way home @ 70mph it was like I was in a blender being tossed around. Took it right back the next day which started a month long process of new tires, then new rims and the dealer checking the drive shaft to ensure it was balanced by that point I told them that I was done with the truck and wanted a replacement. They did and for a 1k more I got a brand new 2015 with several upgraded options and I made sure to test drive it for a good hour and a half... No vibration so I thought I was good to go.. I was wrong, after 500 mile all the same issue started to come back plus many more.
Steering wheel viberates at all speeds
Between 45-70 the center console viberates off and on as so does the gas pedal
Now the door on the drivers side sounds like the wind is blowing right through it when there is any type of cross winds out and feels like it never really shuts unless u slam it as hard as you can.
Next is the hood which has been adjusted but is like a fluttering bird wings when there is any wind out and also at speeds over 70mps.
Last is the Mylink which will not play a single one of my iPods "3" but states it is compatible with each of them..BS.. I finally bought an iPod touch 32g 1st generation which plays but has some delay to it.
So far on the 2015 I went ahead an replaced the rims with stock 20' chrome LTZ rims and replaced the tires with Nitto Terra grapplers AT, have had them road forced twice and the truck still viberates.
This is so very disappointing and an issue that really needs to be addressed by GM!!
I guess my next step is to get the drive shaft checked, the U joints and have the ring and pinion checked as well by some one other than the dealership.