weslp00

Hi Guys,

Question ..... did anyone ever sort out the above.

I have read hundreds of threads on here about the damn rear passenger side clunk that seemed to come from the factory in some instances and no one has ever mentioned a final fix it even after replacing and tightening everything it is STILL there !

You know the one, that annoying little clunk that happens going over rail tracks, cracks in the road and small potholes. And from the right hand side too. Sounds like an exhaust knock.

I still have this issue and after lowering the car it got marginally worse but I cant fix it.

I have modded the suspension with LCAs, relo brackets, torque arm, PHB shocks, lowering springs .. and everything has been gone over a hundred times. Even gone through the radio antenna and spare wheel thing too.

Cannot for the life of me figure it out. The only thing I can think of is the C clip axle rattle thing where the axles clunk when they are pushed in and out with car off the ground. Is this what we are hearing going down the road as they move in and out slightly?

Soooo is there anyone out there who worked this out or are you still driving around with a clunk in the back seat ! ???

Please let me know as I want to kill my car !

JD_AMG

Mine ended up being the rear LCA bushings being shot. The rubber fell out in my hand when I touched it. Replaced with UMI rotojoint LCAs.
A clunk still could be a number of things though.
What bushing material in the LCA's did you go with? Poly will bind possibly make a clunk or squeek and rod ended can make noise.
What shocks did you go with? Inferior shocks on lower springs will never yield good results for anything, could have your car riding way worse than what it should causing things to clunk or rattle, the stock shocks were notorious for this as they were terrible at best even when brand new.
Could actually be exhaust too, hitting somewhere on the underbody or heatshield or a lose hanger clunking.

weslp00

Thanks for the reply !

Been there and done that.. I replaced the LCA's with BMR items with rubber as opposed to poly as I wanted a better ride and used Viking shocks all round. All good quality stuff from vendors.

Checked the exhaust and heat shields.. no binding or looseness.

I'm veering toward the c clip axles moving around. And definitely more noticeable after the lowering springs were put in..

Anymore ideas out there?

JD_AMG

This is why I asked about the mods, fyi Vikings are not good shocks for anything but drag racing, and won't leave you riding as good (and certainly not handling as good) as you should be (especially for the money) - hence increasing the noise. Unless you strictly like to drag race and nothing else Id pull those things off and sell them to try and recoup as much money as possible and buy good shocks (bilsteins, konis, UMI/strano Afco coilovers for example) - you will love the difference they make in how the car drives.
You could be right about the c-clip though. Put the car on jackstands and pull the try pushing/pulling on the wheels and see if you can replicate the noise.

RevGTO

iTrader: (12)

Having the same issue lately, I thought it had to be the exhaust because of the hollow metal sound. Got it on the lift and everything was tight. Checked for loose upper shock nuts and they were fine.

My buddy who runs the shop thought it might be bad rear sway end link bushings, but it sounds too hollow for that.

weslp00

Sounds like we got the same issue! And mine is deffo coming from what you would imagine is the passenger side end link of the PHB. But mine is done up tight with a good quality bushing so it cant be that.
Also the exhaust hanger is just next to it and it sounds like it could also be that. I am running a heavy SS 3" system but how can it be rattling when its not touching anything?
RevGOTO have you checked the play in the c clip axles, maybe they could be causing it ..do you even have the original 10 bolt I wonder like me ???

weslp00

I get a real good ride from my Vikings.. they work well with 19" rims and low profile tyres.. I tried Koni SA's and they were harsh. Least ways with the Vikings they are 2 way adjustable
The clunking is deffo similar to the noise you get when you pull axles in and out like you suggest. They move 1/8th inch on my car which is in limits but could that cause a noise and why do I hear it and no one else comments on the same thing ??

weslp00

bumpp

Tracer Bullet

iTrader: (2)

When I had a clunk from the right rear it was the sway bar end link.

bad_408_vert

iTrader: (6)

Subscribing.

I thoufht it was my old suspension but everything has been replaced with quality aftermarket stuff and that noise is still there. I was thinking it was my spare wheel or exhaust also.

Can it possibly the rear end hitting if the bumpstops are non existent?

M4N14C

iTrader: (3)

Yup same issue here, it's been driving me crazy...

Rear suspension mods:
- Koni yellows single adjustable
- Strano 22mm Hollow sway bar
- New BMR endlinks
- UMI billet aluminum sway bar mounts
- UMI roto-joint LCA's
- Founders Performance LCA relocation brackets
- UMI adjustable torque arm
- UMI torque arm relocation kit
- MWC Fays2 watts link
- 18x11 Forgestar F14 with 315/30/18 Toyo R888's
- Detroit trutrac w/4.10's

... basically the only thing stock back there are the axle tubes. Before I had loads of creaks and rattles, most went away when I dialed in the correct pinion angle surprisingly. Now it's dead silent except under the conditions that OP described; railroad tracks, rough roads, potholes...etc. Driver side seems fine but most of the clunking seems to come from passenger side.

And I know its not my exhaust because it's dumped before the rear axle

stp001

I know that you mentioned that you checked it, but try taking the spare tire and jack out completely. Then take sway bar off. You can at least eliminate 2 things.

Darth Cypher

I've been having a clunking sound coming from underneath my car as well. I rebuilt my front suspension over a year ago (see sig). Several months ago I replaced my rear LCAs with adjustable roto-joint ones. Weeks after that was when the clunking sound started. I just put my stock rear LCAs back on to rule out the aftermarket rear LCAs. Hopefully it will be gone. It happens a lot when I drive over the gravel parking lot at work (I park way out in the boonies all by myself).

weslp00

Hey RevGTO.. I hear you about this and I have been doing some digging and its a Zexel Torsen thing and not all of them suffer with it !
I thought I was right about the axles sliding around in the rear end a slight amount. Evidently, inside the differential, the paddle in the middle between the axle ends rattles as well. And seeing as I have gone to a taller wheel and lower profile tire it gets a shake, rattle and roll even more.... this is all starting to make sense now.
They call it marbles in a box.. sort of clunking that is to me so that could be my problem.

Just because yours/ mine seems to come from the right rear it could be both sides but you just cant hear it from the drivers side ?
I drove the car today with a bunch of dust sheets all over the back seat area and it quietened it down some. so I am considering sound deadening the whole thing.
LOADS of people on here are pissed at the Torsen axle !

RevGTO

iTrader: (12)

I had the "marbles in a can" sound from the original Torsen 2.73 carrier that was in the car. It was a completely different sound that what I'm talking about here. That was like shaking a bunch of marbles in a can; it happened especially lugging around corners and had nothing to do with bumps. This is an occasional clunk when going over the bumps we've been describing.

That being said, I replaced the original carrier with a SLP take-out 3.42 unit over 100k ago. No "marbles in a can" since, except when lugging when the converter's locked. And so, the answer is, no I haven't opened the rear end up except for fluid changes since, so it's theoretically possible that there may be some play somewhere in there.

This unit took a lot of abuse for several years at the track, so that may be a factor, but overall, it's been flawless in terms of noise and performance.

weslp00

Guys I think I have worked it out at last ! I can actually replicate the noise.

I am in the middle of my latest project and have stripped out the interior to do some sound deadening. Supposed to be a good deal

I was jumping around in the back and the same clunk/bonk appeared with short sharp movements up and down in the rear of the car.
I can make the noise appear and its coming from the top shock mounts in the back hatch area. I swear it is the same as when I hit those short sharp bumps on the road. Not the can of marbles thing. And its coming from the same place on both sides.

Its also happening on the drivers side too but I don't think we will hear that so much because it is behind us.

I am using Viking shocks but I had the same issue with Koni SA's like one of the other posters on here but I don't remember it before I lowered the car and changed out the OEM shocks.

So have the original De crappo Carbons got an anti clunk thing built in and why do they put that chunk of foam in the hole behind the carpet! I think aftermarket shocks may be built differently.
Go check it out for yourselves..drop the back seat and pull the foam out above each shock mount ( may have to cut the carpet where it is marked) and bounce up and down. Its as plain as day. Maybe it wont do it with DeCarbons. It could be the stiffer valving causing a knock through the rubber dough nuts ?

The shocks are brand new so I don't think this is going away apart from with my sound deadening project all over it ! I ill cover up the up shock mount and hope I don't need to get to the fasteners..lol and cut a hole if I have to

Get back to me guys on what you think !

M4N14C

iTrader: (3)

For me that was a separate noise that was fixed by tightening the nut on the top of the shock tower. More of a squeak than a rattle/clunking from the rear.

As for this sound I'm almost convinced it's the LCA's. I think I may still have my original stock LCA's with the nice and soft rubber bushings somewhere, I'll try and swap those in for my current Roto-Joint LCA's and see how the noise changes.

weslp00

That's a good idea..I have BMR's on mine but I opted for the rubber bushes as opposed to poly/roto. It cold be coming from them.
The factory bolts are smaller than the frame bolt holes I've noticed so could rattle if not torqued. Don't think that is my issue as mine are really tight and the noise is coming out of the top of the shock mount.
I had my GF in there with me bouncing around and I could "feel" the knock ( non metallic) in the shock fittings on the top sheet metal both sides of the car. Those mounts are down up to speck so it could be a characteristic of these shocks.. more annoying as they work perfectly well... check it out.

Darth Cypher

I swapped my rear LCAs back to the stock ones and the sound is still there. At least I ruled the rear LCAs out. The hunt continues. Car is up on ramps now so I can check the front. It's just too hot out now.

RevGTO

iTrader: (12)

I had that issue once too, and that's what my first thought was - the right rear upper shock nut(s) have come loose. But no - they were tight.