Update: I can induce the noise when the car is in the air and I jack up the axle. The noise seems to come from the differential. Also, it seems to be easier to reproduce raising the right axle rather than the left.
Here is the video (not sure why it's not embedding):
[media]https://www.youtube.com/watch?v=78_AUbSJ-6w[/media]

Update 2: Went out and took another video from under the car. It's hard to see and hear exactly what's going on, but this video makes me think it isn't the differential mounts.
[media]https://www.youtube.com/watch?v=FhVnqWuVpKg&feature=youtu.be[/media]

Update 3: Disassembled right rear shock....dampening seemed normal....nothing visibly broken. Sound seems to be happening more often.

Update 4: Not the shocks....sigh (of both relief and frustration)

Update 5: New reliable way to make the sound. https://www.youtube.com/watch?v=4F7AFFsf3Qc

Solution! Bulkhead replacement bar hitting the fuel tank bulge behind the drivers seat! Took me taking apart the entire rear suspension to come to that conclusion lol.


Original Post:
A few months ago I started hearing a clunk/rattle just behind me while driving. For the longest time I thought it was some tools in the trunk hitting each other. I've since removed everything from the trunk and am still getting the noise. Here's what I know so far:

-No spare in trunk
-Doesn't happen at moderate to high speed
-Happens most often under uneven load like entering a slanted driveway at an angle.
-Not rear sway bar
-No obvious tears in any rear rubber including diff mounts
-no obvious seepage on the shock.
-Top shock nut is tight
-Recently had an alignment done by a terrific shop so all adjustment bolts are recently tightened.

Would a metal to metal clank and sometimes rattle point to a blown shock? It seems unlikely. It should be noted too that the entire interior behind the seats is gone and I have a double diagonal roll bar bolted in. I'm coming up at a loss apart from replacing or swapping the shocks. Thanks in advance for any help. I'll post a few pictures here shortly and may try to take a video.

 

If it is a metalic clank it could be the rear pads, I had a MY 06 and drove myself nuts trying to fix the rear "pad clank". Bought an 01, and it does the same dang thing! Not even the same pads! I just get a metalic chink sound over bumps, although mine happens over sharp higher speed bumps.

 

Thanks bgoetz. I hope to get a video soon and maybe you'll be able to tell if it's the same kind of sound you've had. I don't actually mind the sound as long as it isn't a sign of a failing part. I've started tracking the car this year and so I'm probably hyper sensitive to any noises at the moment.

Also, it probably has no affect on whether the noise goes away or not, but I have swapped the pads and it had no affect on the sound.

Here are some pictures that I'm sure won't help at all, but just in case.

 

I guess too, I can try tomorrow to induce the problem but hold the brakes over the bump to see if that prevents it. I would love to find out that it's just pad rattle.

 

Pull the ebrake just a bit a leave it up, that is how I figured out it was the brakes on both my cars. IDK why mine have done this, but both I have owned have.

On a side note every car I have tracked has made poping/clunking sounds that I just end up chalking up as "normal". For the most part, if a suspension component goes into failure mode, it will surface and be very apparent before failing. If your car normally makes the noise with no ill consiquences then it is normal. Noticeable changes in the sound or new sounds are what you watch for.

 

Hmmm....

Held parking brake both lightly and aggressively and it had no affect

Stood in the trunk and bounced up and down hard an no noises.

Had my wife stand outside the car and then sit inside the car...the noise is much louder from the interior.

 

Ok, went out and took a couple videos at different angles.

First Angle...Clunks/Pops at 0:14, 0:27, 0:39, 0:47
[media]https://www.youtube.com/watch?v=vmAkcylPdRM[/media]

Second Angle...Clunks at 0:04 and 0:17
[media]https://www.youtube.com/watch?v=SqtzxZll35c[/media]



Thanks so far for the help!

 

Mine does the same. Also interested.

 

Back from vacation. Time to start chasing the noise again.

I'm thinking of putting a jack under each of the rear jack points and raising them to see if it's chassis flex causing the problem or suspension flex.

 

Ok, Update.

Got the rear of the car in the air and on jack stands. Used a piece of wood and a jack stand to put load on the wheels. Could induce the clunk. Got underneath and it sounded like it was coming from the differential and not any suspension pieces.

Could this just be a sticky differential like the kind referenced here (https://www.s2ki.com/s2000/topic/875...tial-clunking/)?

Could it be the differential mounts? Should I be concerned at all?

Thanks again for the help.