Gm customer service is useless,I have been dealing with vibration on my 14 Sierra since new. I finally contacted the bbb and guess who calls the next day. After a couple weeks of back and forth the rep tells me yesterday there is nothing wrong with my truck and he has nothing to offer for the countless times at the dealership for the vibration and many other issues and I need to go toward with the bbb since I didn't like his answer. My truck is in the shop right now and the 16 sierra I'm driving is also a vibrator with wheels.