Thought I would share a symptom that turned out to be the passanger side unit bearing.

I would feel a slight vibration in the steering wheel and through the floor boards when I turned the steering off of center. It turns out the passanger side unit bearing was in the process of eating itself alive. The inner seal appears to have failed and then the bearings stated to go. My Daughter and I replaced it today and problem solved. This is a 2006 extended cab 4X4 with less than 30,000 miles on it of all highway so I'm a little PO'd that it failed in the first place.

The main reason I'm posting this is I have seen many threads that talk about a vibration when off of center a bit and all sorts of statements like it's because the frame is a big tuning fork, or it's because of the rear differential, or it's because of the rack and pinion. It's easy to check if the unit bearing is bad by jacking up the wheel and rocking the tire back and forth by grabbing the top. If you have any play and the ball joints aren't moving, you have a bad unit bearing. Break out the checkbook. They are expensive, but easy to replace.

 

Just had the same thing happen to mine, 06 4X4. It would shake and hum when turned off center, kind of sounded like I had mud tires on it. But anyway I took it to the dealer and luckily they replaced it under warranty.