I have a 2014 Silverado z71, has had the driveline vibration since brand new. Went to dealer at 1200 miles, was told no fix and to keep driving it. Had a shop install a 3.5" lift and now GM won't even touch it. I have bought GM trucks for the past 20 years, and this will be my last. I will never own another GM product again. Beware to all who buy the new truck. Please test drive them for vibration before purchase!