I bought a `99 F150 4x4 three weeks ago and finally just got it back from the shop after having the pass. side head replaced. I started hearing a clunking noise under the cab when turning. You can feel the clunk with your feet. At first, I just thought it was ice falling off of the chassis, but it is now 40 degrees out and dry and the noise is still there. It doesn't happen all the time, which I fear will get me nowhere at the dealer.
Could it be a torsion bar binding? Any common problems with that?

 

Oops, I looked back at some of the old pages and found the likely culprit; a loose cab mount. I'll check it out. Sorry for the laziness.