So the clunking is still present in the rear of car and slowly getting louder. The struts and spring all seem tight. Could the strut mount be going? I find it's also affecting the steering/handling of thecar. If it is this, the problem, would it be easier to change the affected parts, or to swap in new aftermarket quickstruts? Thanks fab

 

You sure its the struts & not a lateral link? I ask since you mentioned it affects the steering/handling.....Very well could be a rubber bushing is worn out/shot......Get it up on a rack & have a look....What work have you done? If I was replacing the struts, I'd would of replaced the strut mounts both front w/ bearings as well as the rear bushings.....

 

Felix, i had the rear sway bar links and bushings changed. I had suggestions of the lower knuckle bushings maybe the culprit, but even my mechanic said they looked good. I'm not sure what other tests i can do on the suspension to see where and what is the problem.
fab

 

Try getting the vehicle up on a alignment rack & grab the rear bouncing it by pulling on it, to see if you hear or see any slop in the bushings.