NEW Dodge 2013 Ram 3500 4x4 -> ride is horrible! What to do?

I used to have the vibration, then I rotated my tires. I got vibration after about 10k or so miles. Then after looking at my owner's manual, I saw that 7.5k rotations were in order. I ran my tires out to around 15k on each axle the first 2 rotations, it didn't like that. I'm now on 7.5k and it made a huge difference. I'm wondering if there's some sort of oscillation occuring between the frame and suspension. I plan on upgrading to some Bilsteins anyway since it's cheap.