2003 Yukon Front Suspension "Loose"

I have a 2003 Yukon XL 1500 4WD with approximately 120k miles. I have recently noticesd that the front suspension feels loose or "jiggly" when going over bumps almost like I was riding on Jello. I just had the truck inspected and asked that the dealer look for any problems. They indicated that all was OK. Since then, I replaced the front shocks, even though the originals semed OK, with no change...still loose. I asked the dealer specifically if the internmediate shaft was lubed and they indicated that it was OK although I only get a clunking noise going over larger "sharp" bumps. I called the dealer and they suggested bringing it in to see if they can find anything but I can not afford to have them randomly trouble shoot at my expense. Can anyone suggest where I should look for the problem?? Any suggestions would be greatly appreciated.
Thanks

Control arm bushings, ball joints, any steering linkage, gear box adjustment, wheel bearings, to name a few things.

Thanks, I guess I should have expected that response. I was hoping for something a little more specific like a "this is a typical problem with Yukons" kind of response, like the intermediate shaft problem that is a fairly common problem.
Has anyone else experienced this kind of issue. This developed pretty recently probably in he last 5k miles.

If it is clunk you can feel as well as hear even going slow over little bumps and turning it is probably the intermediate steering shaft. The shaft has been revised. If where the shaft bolts to the steering column inside the truck is a silver cylinder before the u-joint, you have the old style shaft. The new style is less bulky and looks more like a regular u-joint at the bottom of the column. The TSB procedure changed a dozen times at least, lube it, do this, do that, none of which worked for any length of time. Now there is a new style shaft available that will solve the issue.

Thanks I am considering replacing the shaft but I see comments in various forums about damaging the "SIR Coil".
Does anyone know what the potential damage is and more importantly what I need to do to prevent damaging it?
Thanks

The steering wheel must not be rotated when doing this as too may turns either way will seperate the clock spring.

Thanks, so it sounds like reasonable care will prevent damage?

Correct, try to get the wheel centered, then careful not to go more than half a turn either way, even find a way to lock it in place once the shaft is disconnected.