Hey Guys,
I had this problem and saw all kinds of possible driveline solutions. I had a 2004 truck with this problem. There is a 2003 TSB for a replacement upper power steering hose. They performed this TSB on my 2004 and it fixed the problem. Here's how to tell if you need to have it done...
Open the hood and look at the two power steering lines on the driver side just inside of where the battery sits. The top line should have a big weight attached to the line. It looks like a "C", maybe about 2 inches by about 2 1/2 inches or so. If you see it, this steering TSB won't fix the problem. If don't see the weight, go this route.
The added weight to the high pressure line dampens the vibration to the steering wheel. Some people say the actual cause of the vibe is the exhaust bracket on the side of the transmission. Not sure why DC would do that, but they did. Anyhow, if you look at your line and have any doubt about having the weight -- you probably don't have it. You can't miss it, the thing is huge.
Anyhow, hope this is helpful info!