new tires helped some /allignment checked good /once every few months makes loud rumble from rear that lasts a few minutes then disappears . vibration is present even at lower speeds / can feel it even thru steering wheel and dash and floor / 55,000 miles .when going over 70mph , there is a deep humming sort of sound .

Been to the dealer 5 plus times for my vibration in my truck. The passenger seat will shake. The cub holders will shake when they are in use. The dealer has replaced the tires, force balance the tires several times and replace 2 faulty drive shafts. They claim these truck ride rougher than the 1500 trucks. My truck has 20" rims (factory) Z71 package, ext. cab. From what I reach search so far, there is a lot of complaints about this. Is there a solution. I file complaints with the Chevy customer service, but that is a waste of time. The truck has been in the shop after the first 1800 miles on it, and I'm on 33,000 miles and mad as hell that no one will fix it.