Thumping or Klunking noise in rear suspension

[lskipper]

Greetings,
I have tried to search this subject, but it seems to a very broad subject.I have 2007 Tahoe with about 71,000 miles on it. I haven't made any mods on it.
There are times that I hear a klunking noise coming from what I believe is the right rear. It does not make the noise when it hits a bump in the road, but does make it when the for lack of a better description, the body flexes up and down ( example -going over a speed bump). The frustrating part about this is that it does not happen all the time, but often enough to be annoying.
I have read it might some linkage or it might be something in the rear end.
It is still under warranty, but I would take it to the dealer with something definitive. I have been underneath it but don't know what I am looking at.
Any guidance would be appreciated.
Linn

 

[Modded]

I use to have a clunk come from the rear too. One was due to my drop coils (solved by swapping them with other drop coils) and the other was due to loose rear door striker plates.
Mine got real annoying and would sound like a clunk coming from the rear suspesion over certain road conditions just like yours (speed bumps especially). Took it to the dealer and they blamed the drop kit, later I figured it out to be the strikers and they replaced them for free, now I am clunk free.
By the way, the strikers are the u shaped hinges in the rear door jamb just for a reminder.
Best way to test is ot your finger around them and yank them around, if they move at all they are loose/messed up. Instead of them moving, the whole car should move, not just the striker.