87 300E steering noise

[gloucesterman]

Mein auto has developed a new sound to keep me up at night. A sort of clunk. Happens when changing direction either way, but only under load (pulling out of a parking space, turning from a stop). The greater the load on the steering linkages, the more pronounced the clunk. Seems to be in the area of the driver's side tire. I've looked under there but no obvious damage. I also get the same sound (much reduced) if rounding a curve with enough speed to stress the suspension. Under that circumstance, I don't have to be turning the steering wheel at all. Thoughts, anyone?