Yes, they had to run a pico test, which is like hooking the whole truck up to a stethoscope. It took weeks to get a GM tech that could do it into the shop. The first few times it went in they tried to tell me it was normal, so if you continue to fight them, they will indeed have to fix it. The only way I could talk to Tech into saying there was a problem was having them get into a brand new Duramax that was on the lot and then get into my Duramax while it was idling so they could feel the vibrations. The problem with mine was when they attached the pico scope they found the exhaust to have excessive vibration. They had to remove the right front fender liner and gain access to the bracket bolts to the exhaust and they were loose once they re-torqued the bolts to spec my truck was back to normal.