Since no one else has responded I will give a rough guess.

The CV boots have to contract and expand since your going left to right and back. Just look under there and you see the ribs which allow it to stack and expand. Possibly when you are turning them and causing them to expand, the CV boots are "popping" or "clunking" apart?

Check your Power steering fluid as well as a low level can cause really weird noises.

E0 #4384 of 6535 Born Jan. 9 1998 My SVT from the ashes 147,466 miles, purchased Nov. 2002 @ 76,559 miles