I just had my '03 XC at the dealer for 22.5K service and mentioned to them that my car had a pull to the left. Upon inspection they informed that my tie rod linkage on the left front was broken and replaced it under warranty. When I got home and mentioned it to my wife she says "it that what was causing the clunking sound?" My response was "what clunking sound and why didn't you tell me you were hearing a clunking sound?" She drives the car everyday and I maybe drive it once a week. I never heard the clunking sound prior to the linkage being replaced and I haven't heard after the linkage was replaced, so I can't describe it to you, but I would ask your dealer to check these parts.
2007 XC70/Rubyred (Hers)
2003 XC70/Platinum Green (Daughter's)
2001 V70/White (Son's)
2009 Mercedes C300 Sport 4MATIC (Mine)