I've searched and looked at numerous threads regarding this issue and the most informed one were by Mr.Dummy here
The clunking/knocking noise ONLY occurs after the car sits overnight in very cold New England weather.
Here are some of my observations:
1.) Occurs in cold weather only
2.) Loudest when car is off and turning the steering wheel left/right
3.) After you start the car the noise is not as loud but it's there
4.) After the car warms ups the noise doesn't clunk but clicks.
It seems the way the car is park will determine if it'll clunk or not. For example if I back up into my parking space the sound will be there in the morning but if I park normally than the sound will most likely not be there in the morning. As far as I can tell my garage parking spot is flat.
Just got a call from the dealer they said couldn't reproduce the noise even though I showed my SA the video. I'm going back there tomorrow to try to show the video to a shop foremen or service manager. Any ideas of what this could be? My steering column was replaced as part of the recall a few years back.