Tires: Vibration in steering wheel and seats at high speeds, cv joints, brake rotor

Question
Everything on the truck is stock, there has been no lift kit or any change to the leaf springs. Also rotating the tires does not seem to affect where the vibration is felt, it is pretty much felt throughout the truck, from the seats to the steering wheel, even my side mirrors shake. So if my pinion angle is off, what would be the fix for that?

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Followup To
Question -
Barry,

I have read most of the posts concerning similar problems, but I have still not been able to solve my problem. I drive a 1998 GMC Jimmy 4x4. When I first purchased this truck a year ago used, I noticed that I had some vibration at high speeds - 60-80. I thought that the problem could be bad or unbalanced tires. Recently I decided to get new tires and see if that would solve the problem. No such luck. The dealer claims that the tires are balanced and I have taken it back several times. Also they claim that I do not have a bent rim. I have also had the CV joints replaced. The vibration is really starting to become a bother. Any suggestions? Your help would be greatly appreciated.
Answer -
Eddie,

Assuming the truck isn't lifted, the pinion angle could be off.

If it is lifted, that is PROBABLY the source.

Hope this helps.  

Answer
Eddie,

I've had some additional time to think about this and have come up with a couple of other possibilities.

First the pinion angle.  What's the fix?  Adjust the pinion angle until it is in the proper range.

But one of the other things that it might be is the driveshaft balance.

Although this doesn't make sense since you feel the vibration in both the steering wheel and the seats is some other ortating component that is normally ballanced and normally stays in balance, but has become out of balance, like a brake rotor.  I really don't think this is it as you would feel this in one place and not the other.


Hope this helps.