Thanks, battery was the first thing I checked. Your right about the horizontal exhaust movement. There is little vertical movement but quite a bit of horizontal movement. I may take the hangers loose and try to reposition them. They might have a little adjustment.

I havent had a clunk in the rear but I have had it in the front driver side. GM said that they fixed it the 2nd time I came in with a bushing. Nope still there. Its going back in on Tuesday.

Exhaust systems are meant to move some on every car. However, if you’re moving it enough for it to make contact with other components such as the uni-body or chassis/suspension components, that'* a sign the hangers themselves (the little rubber things) are probably stretched out and/or loose.

I noticed this in the rear of mine this morning coming to work but it may just be some of the loose stuff I have in my trunk.

If it is something in the suspension, you should be able to note it when driving repeatedly over the part of the road causing the noise as to whether or not it'* a suspension clunk or something clunking in reaction to the vehicle'* composure. Chassis problems can sometimes be difficult to diagnose as when you're checking them out in the driveway, what to yo physically may be tight, may not be when 3,600 pounds of car are on it. Unless you somehow magically can hang under the car while someone else drives.

Whatever is loose seems to be REALLY loose. The clunking is THAT apparent, and gets much louder and more rapid as dictated by the degree of bad surface I run over. But it takes a pretty rough section of road to get it started. It won't do it on an average street. It takes something like a rain gutter + uneven surface to set it off. Then it goes away just as quickly. I can't find anything loose. Maybe I'll climb in the trunk and let my wife drive me around :P I'm old enough to remember the drive-in theatres in high school.

I noticed a clunk in the rear of my GXP too. When I was changing the rear rotors I noticed the passenger side coil spring was not even close to being mounted in the center on the top mount. I tried to rotate the spring but it still is not looking correct. I am looking for a replacement spring today and can post pics to explain this better.

I still haven't fixed mine yet. Dealer is no help. Let me know if the spring repair did the trick. I'll be crawling under mine this weekend (for the tenth time) and check those springs out.

It could very well be a wore strut, and/or wore strut cap/hat that holds the spring on, keeping it under pressure. This would cause the spring to bounce some and even rotate.

It could also come from improper installation of the spring and cap if you've had the struts replaced recently.

Dealer finally fixed the problem. I had some other warranty work being done and I asked them to look at it again. First they said it was the shock mount. Some of you have suggested that, and also had that problem. Well the mount replacement didn't fix it. Thankfully the service manager admitted that it wasn't fixed before returning the car to me. They ordered a new shock and put that on. The shock was the problem. I never heard of a shock clunking unless it was loose or broken at the mount. ??? Don't know what would make a seemingly secure shock clunk. Anyway, the shock was the culprit for everyone'* future information.

Glad you got the problem fixed. Thanks for posting!

i had the same problem, and when it was on a lift you see that the pipe about midway between muffler and engine is in a u shaped piece of metal for protection and yes it does move that what the clunk sound is, the only way to stop it to put something between exhuast and side rail to space it