I have an 03 2500HD GMC, the steering shaft started the klunking noise and got worse. I looked and the posts in the DIY section and decided to pull the shaft before I took it to the dealer for repars. When I pulled the shaft I noticed that the lower screw was tight due to having thread locker on it but it was only slightl tight. Did not have torque wrench. I pulled the shaft out to find that it was well lubricated and it would slide in and out slick as a whistle. I re-installed it and tightened both end pretty good. This got rid of the knocking. It appears that the fit of the bottom end of the shaft is a rather loose fit with the lower shaft and this may be where my knocking was coming from.
FIY truck has 10500 miles.

What happens is when you remove the shaft and slide it in and out it redistributes the grease. The clunk eventually comes back and will need to be relubed.

There is a TSB for this and on some 05's a recall - for the intermediate steering shaft.

I just had my intermediate shaft replaced due to a knock in it at 14000 miles

Is the new shaft a permanent fix? I'd rather not have to lube this thing every 15K miles.

Thanks for the help in advance.

The stealer told me it was,so we'll see. They said they were haveing problems with them. I had to wait 6 weeks to get the part,it was back ordered.

Looks like the idiots from GM would learn by now. Ya know its only been 5 years now !

Where exactly do you guys hear the knocking / cluunking sound from? I thought I had the steering knock so I lubed the shaft(thanks Eric). And this did nothing for the noise I have. Mine sounds like it is from the front left tire area, I don't feel a thing in the steering wheel, and I can hear it up to 50 mph on certain roads. It is actually worse in the cold weather. Help !! thanks, Mike

Just had mine replace after 46K. Slight noise, but eough for me. Took it to the dealer when the PS pump went out (no brakes or steering) and since the TSB was not covered in the extended warranty, they REPLaCED it so there would be no additional cost to me! Man I think I found a dealer/service group that is about the best going! The only cost to me was the $100 deduct for the PS pump, & they checked ton of other annoyances and the steering shaft for nothing.

Mine was more of a felt clunking. Sort of like your wheel rubbing suspension components on a tight turn? Had the shaft replaced and problem solved ~ better'n new in fact like a completely different vehicle.