2004 Chevy Tahoe

Is the vibration any different if you are accelerating? If so is it worse under mid-throttle or full throttle?

Does the load on the truck, like going up a steep grade, affect the vibration?

Are the tires larger than stock?

There are a few things it might be, so you will have to use process of elimination to find the issue.

The more likely, cheapest and things that need to be routinely anyway should be done first.

Look at the passenger rear tire and see if the tread is worn unevenly. Make sure tire pressure is correct all around and if you have not rotated and balanced in a while, do so and see what happens.

Rotating and balancing tires on bigger trucks is important as disregarding to do so will wear out tires, bearings and axles more quickly.

Let me know how it goes and I will help out as much as I can.