Persistent clunk post RACP repair / rear end refresh (video evidence)

[Nate047]

Alright guys, I hate to do this but I need some guidance. I have videos of a very annoying clunk / clanging I'm getting from the rear of my car after a substantial rear end refresh and RACP repair. I'm going to try to be thorough to make this a worthwhile thread and not just "let me look into my crystal ball and see what's wrong with your car."

Essentially its a loud and very clear and obvious clunking / banging / clanging sound that presents over all bumps, big and small. It does not change one way or the other under acceleration, deceleration, or cornering. It's just when I go over bumps on the road surface. The car seems to drive fine.

Here is what I did to the car:

Redish plates welded on underside
Yurkan Cages 6-point upper brace
CMP solid subframe mounts
KW Clubsport
Rogue Engineering monoball rear shock mounts
SPL rear camber arms
Stock upper control arms, and new stock bushings inner and outer
Hotchkis sway bars
Had Powerflex diff mounts but replaced them with stock (this resolved a different drivetrain related clunk)
New parking brakes
DB9/996 Brembo caliper retrofit

Also I gutted the rear of the car so everything is louder as a baseline. I thought for a moment (and maybe this proves to be true?) that maybe it was a socket or bolt that like, fell into the body of the car somehow LOL. But I cannot recreate it by tapping on the car or jumping on the trunk to make the car shake a little. It only presents while driving.

Here are the videos, please take a look with good speakers or headphones. These are each less than 2 minutes so if you watch the whole videos, you will 100% hear the shit I'm talking about.

Angle 1: middle of car, looking straight back. The sound kind of sounds like it comes from both sides, maybe a slight bias towards passenger. Can hear it well starting about 18 seconds in

https://www.dropbox.com/scl/fi/grjt2qw8s1oppu6wajg8u/Angle-1.mp4?rlkey=e0l3kjt27uazbrwiaw8sd7924&st=3l44gxri&dl=0

Angle 2: Focused on shock tower

https://www.dropbox.com/scl/fi/pr2htnb24qplipx1oewbi/Angle-2.mp4?rlkey=qvkh073t1kj21t6x5sv0wjdt3&st=ivhsmkll&dl=0

Angle 3: not a very good video, but you can hear it still

https://www.dropbox.com/scl/fi/u771l0kx6rhbp954r6ncp/Angle-3.mp4?rlkey=3dmphp9479gk7y7q90xmss0mh&st=w8l1wbjh&dl=0

Angle 4: Underneath the car, it's much more faint down here TBH. I know what the drivetrain and tire noise, gravel, etc is. You *can* still hear the clunking but it's very much not front and center. So maybe that indicates something about the source.

https://www.dropbox.com/scl/fi/1ag7ki9en8oy4tnd4q02e/Angle-4.mp4?rlkey=zqs8dpfiq7d9ykvyyxq101bsq&st=uygr4lo7&dl=0

I thought maybe it was the sway bars so I pulled the bar off, problem persists.

At this point I'm leaning towards upper shock mounts, or the 6-point brace. The brace is on there tight but I dunno? I have been under the car a bunch of times in the last few days, checking, test driving, checking again, and everything is staying tight.

Kinda running out of steam on this over here guys, LMK what you think.

[1000hp]

Get yourself a chassis ear!

If you're not familiar, this is a device with a bunch of little "microphones" that you clamp on in suspect areas. You can then listen to each microphone individually through headphones by selecting that microphone's channel on the device.

The noise will be loudest through the microphone nearest the problem. They are a huge help in locating noises that occur while driving. And they're cheap.

https://www.tooldiscounter.com/product/steelman-chassis-ear-ste6600

Also, when I did my subframe and full rear end refresh, I spaced on torquing down one of the RTAB cross bolts (the bolt through the center of the bushing) and it made a loud clack over bumps. Might want to check those.

[jayjaya29]

Its your Rogue Engineering monoball rear shock mounts. 100000%, switch to a rubber alternative like this: https://www.rogueengineering.com/Rogue-Engineering-E30E36E46-Rear-Shock-Mount-Pair_p_270.ht

[fattycharged]

rear shock mounts…just installed them myself and was pretty shocked at how loud they are. It’s so loud that I was having same thoughts as you, like what didn’t I torque properly, something is clearly loose back there, so swap them out and take another drive.
I haven’t replaced them yet myself, don’t have anything on hand for the 12mm, but I’m 99% sure that is it and iirc during install, there is just enough play in the mounting sleeve that I assumed some clacking might occur, but it was more than I was expecting just driving through the neighborhood at a crawl.

[cobra]

Also here to say rear shock mounts.
The bumps comment says it all. Just a small amount of play can rattle really badly.

[Nate047]

FIXED!! One of my great friends happened to have a set of used stock shock mounts. We test drove the car together and he was just like “bro, it’s the shock mounts,” so we went back to his house and threw them on. Test drove again… I’ve never felt such a feeling of relief, to hear the beautiful sound of nothingness.

The Rogue mounts have quite a lot of play in them so I’m going to see if I can return them. There’s no way this is just “how they are.” I’m

So now. I’m going to leave these in there temporarily, but what do we like as a replacement it for these? I don’t even have an issue just running stock tbh.

[Slideways]

FIXED!! One of my great friends happened to have a set of used stock shock mounts. We test drove the car together and he was just like “bro, it’s the shock mounts,” so we went back to his house and threw them on. Test drove again… I’ve never felt such a feeling of relief, to hear the beautiful sound of nothingness.

The Rogue mounts have quite a lot of play in them so I’m going to see if I can return them. There’s no way this is just “how they are.” I’m

So now. I’m going to leave these in there temporarily, but what do we like as a replacement it for these? I don’t even have an issue just running stock tbh.

I would just run stock unless you want TCK or Rogue Buna RSM mounts that allow you to remove the rear damper from the wheel well without having to go inside the trunk.

[Cubieman]

FIXED!! One of my great friends happened to have a set of used stock shock mounts. We test drove the car together and he was just like “bro, it’s the shock mounts,” so we went back to his house and threw them on. Test drove again… I’ve never felt such a feeling of relief, to hear the beautiful sound of nothingness.

The Rogue mounts have quite a lot of play in them so I’m going to see if I can return them. There’s no way this is just “how they are.” I’m

So now. I’m going to leave these in there temporarily, but what do we like as a replacement it for these? I don’t even have an issue just running stock tbh.

I would recommend the Meyle HD's for RSM's or the RE rubber ones.

[fattycharged]

FIXED!! One of my great friends happened to have a set of used stock shock mounts. We test drove the car together and he was just like “bro, it’s the shock mounts,” so we went back to his house and threw them on. Test drove again… I’ve never felt such a feeling of relief, to hear the beautiful sound of nothingness.

The Rogue mounts have quite a lot of play in them so I’m going to see if I can return them. There’s no way this is just “how they are.” I’m

So now. I’m going to leave these in there temporarily, but what do we like as a replacement it for these? I don’t even have an issue just running stock tbh.

Nate, mine weren't Rogue, just monoball, I think BW, same exact issue, so in some ways its just "part of the deal" running a monoball with poor machining tolerances they all seem to have

[Nate047]

Good to know, I’m going to just leave these ones on for now until they become an issue.