Hey all Chevy truck owners!

[MED]

I don't think it's the driveshaft, it's not a constant vibration. It varies with the road surfaces, and it feels like the wheels are bouncing up and down, like dribbling basketballs low and fast.

Is it bouncing in the front, back, or both?

[SouthPaw]

If it is bouncing up and down, that is usually shocks. Depending on how long and severe it has been going on, it may have caused flat spots in the tires. I am on my third Silverado 1500 ('05, 08, and now '15). The '05 road a little rougher probably due to the torsion bar suspension. When they switched to coils on the '08+ it was a major improvement. What load range are your tires? If you don't haul heavy loads and don't tow; I would be looking at some P series tires.

[rondog]

Is it bouncing in the front, back, or both?

Both.