Rattle/Clunking on driver side between the dashboard and firewall

I have a 2004 Avalanche with 160,000 miles on it. I love it. But. It has developed a chronic clunking sound/rattle on the driver's side inside the dashboard but probably before the firewall. Has any one else encountered this issue?

Sounds like the Intermediate Steering Shaft

http://www.chevyavalanchefanclub.com/cafcna/index.php/topic,93023.0.html