Vehicle has a terrible vibration. has been to dealer 7 times, for a total of 4 weeks. a gm engineer has looked at it twice. they have replaced ring/pinion, driveshaft, axle .. tried it with 4 sets of tires/wheels. last idea was to replace shocks, struts, sway bars with hand built parts, cut brackets off car and weld new brackets on. when liability was brought up, they changed their story. there is a larger issue as was relayed by engineer to service manager at dealership. issue is with all 2015 tahoe, yukon, escalades. in an effort to prevent roll overs, they designed the frame and body mounts too stiff. there are 40 engineers working on issues, they have no solutions that work across the board. according to engineer, gm is keeping an eye on how many units they have to buy back, or trade for ... if number is low enough, they will not make any changes to design. i would like to schedule a meeting next week to discuss this issue and the larger issue in person. since they are refusing to buy back my vehicle, i am turning matter over to attorney. *tr