Has anyone had this problem? I have an 05 sSierra Denali, and at about 70-75MPH, the truck starts to vibrate. The dealership balanced the drive shaft and replaced differential fluid, but that did not solve the problem. I know it's not the tires. You can feel it under the truck through the seat. It's almost like a humming sound. Thanks in advance for anyone's help who have had this problem and fixed it. - Matt

 

what size wheel and tire are you running?

 

it is the stock 17"

 

Is the truck the stock height or lowered? Could U-Joints be the problem?

 

It is stock height, and it does not make noise when in neutral.

 

Did you get the AWD version? It might be the Tcase. Best of luck getting it fixed