Here is the solution...I had my "clunk" fixed on Monday, July 9th.
My 98 4Runner SR5 Auto had a clunking sound coming from underneath "somewhere" whenever I made a left turn...OK when going straight ahead or a right turn. I posted the problem on this forum sometime ago but can't find it now, so I'm posting here in hopes that it may help someone. Anyhow, I took it to a dealer. Turns out it's the sway bar linkage on the left front wheel. It was broken. He suggested I replace the right wheel linkage also...seemed reasonable, so I did. Bottom line cost was around $450 parts and labor.