Odd Noise

***JC*** · 04-21-2009, 05:38 PM

It's an 02 TA with 22,000 miles. It has the factory wheels but with the BFG KD TA"s mounted on them.

Recently I've noticed a thud noise coming from the right rear when hitting large pot holes or those nasty narrow but tall speed bumps. It also makes this sound occassionally when angling into a parking lot when turning right from a road where there is a dip. It almost sounds like the tire is coming up and hitting the rim of the wheel well. However, I know this isn't true as I can find no scrape marks on the edge of the tire. I've checked out the Bump backs (those rubber bumpers that stop the axle) they seem to have plenty of rubber left on them... It has an aftermarket cat back but it's had that for many years now and it's never been a problem. I can find no where it's making any kind of contact. Could it be the shocks? They aren't leaking and the car has very little mileage on it so it seems strange that the shocks would be bad?

I'm at a loss to figure out what it could be that's causing this strange sound, So I thought I'd ask here for any suggestions or past experiences others may have had?

***JC*** · 08-01-2009, 01:03 PM

A few months ago i was returning from a road trip and went to pass a car. Well, along this stretch of highway they had those round metal things that are located along the yellow line that divides the two lanes. When my left rear tire passed over those things it gave a slight bump as it would in any car, nothing unusal about it. However when the right rear tire passed over them I thought it was going to beat the car silly... So I ask is this not a faulty shock?

**LSCyaL8R** · 08-13-2009, 10:33 AM

nobody has any idea? I'm having the same issue. thought it was the shocks so i got AGX's and still have this issue. I feel like the axle is going to punch straight through the floor. I wouldn't call it an odd noise... more like a BANG! and it does seem to affect the right wheel more than the left. It must be something to do with the bump stop because when i am alone in the car it doesn't happen too often but put even one passenger and it gets much easier to hit a bump and have it crash like that. scares the hell out of people in the car when it happens.... i'm just terrified that i'm ruining my poor car by driving it.

**vetteemt** · 08-13-2009, 10:56 AM

Just throwing out ideas:

1. posi unit is hanging up and not unlocking like it should.
2. broken C clip in the rear end allowing the axle to wobble in and out of the carrier.
3. other rear end issues bearings etc..

**LSCyaL8R** · 08-13-2009, 01:19 PM

if the axle was wobbling out of the carrier i'd likely have more problems than a bang on bumps... it's not just a noise mind you but a harsh crash... like spine jarring. i doubt a c clip or hung up posi would act that way on a bump.... i think my problem is much the same as the OP. since this is what i was searching for when i found the post. In my research it seems like the springs can be the culprit. I'd hate to think i've busted my new AGX's due to bad springs.... my car seems to ride level and at the right height. but I know I could use some new bump stops... in fact... i think i'll go get some new ones right now... any other ideas are welcome. I'd hate to get springs if i can avoid it. i like stock ride height and don't want to pay through the nose for OEM springs. Car only has 49k miles BTW.

***JC*** · 08-13-2009, 03:17 PM

Originally Posted by LSCyaL8R

if the axle was wobbling out of the carrier i'd likely have more problems than a bang on bumps... it's not just a noise mind you but a harsh crash... like spine jarring. i doubt a c clip or hung up posi would act that way on a bump.... i think my problem is much the same as the OP. since this is what i was searching for when i found the post. In my research it seems like the springs can be the culprit. I'd hate to think i've busted my new AGX's due to bad springs.... my car seems to ride level and at the right height. but I know I could use some new bump stops... in fact... i think i'll go get some new ones right now... any other ideas are welcome. I'd hate to get springs if i can avoid it. i like stock ride height and don't want to pay through the nose for OEM springs. Car only has 49k miles BTW.

I thought about the bump stops but mine look fine hardly worn and after I thought about this issue more. I realized even if the bump stops were brand new it wouldn't make a difference. If the axle is rising up far enough to hit a bump stop new or old it's still going to make a hard noise that shutters through the entire chassie...

I haven't figure out what it is yet and posted the question up on here in hopes someone would step in and offer some advice. But this site isn't what it used to be and friendly help isn't so forth coming these days.

Since you bought the AGX shocks did you check the setting? If you've got them too soft it's going to be like having no shock at all on the rear...

**dklowrider** · 08-13-2009, 04:22 PM

Originally Posted by *JC*

I thought about the bump stops but mine look fine hardly worn and after I thought about this issue more. I realized even if the bump stops were brand new it wouldn't make a difference. If the axle is rising up far enough to hit a bump stop new or old it's still going to make a hard noise that shutters through the entire chassie...

I haven't figure out what it is yet and posted the question up on here in hopes someone would step in and offer some advice. But this site isn't what it used to be and friendly help isn't so forth coming these days.

Since you bought the AGX shocks did you check the setting? If you've got them too soft it's going to be like having no shock at all on the rear...

i would get the car in the air and start one bolt at a time, checking all the bolts, sway bar mounts, lcas, phr, ta mounting, etc. something might show up. might sound stupid, but check the spare tire/ jack mounting too.

***JC*** · 08-13-2009, 06:24 PM

Originally Posted by dklowrider

i would get the car in the air and start one bolt at a time, checking all the bolts, sway bar mounts, lcas, phr, ta mounting, etc. something might show up. might sound stupid, but check the spare tire/ jack mounting too.

I appreciate the help I really do but I've checked all of that stuff... This is why it's such a darn mystery? I'm about to put shocks on as well but if I have the same luck as the poster above I'm back to square one again on trying to figure this out?

**JaycenK** · 08-13-2009, 07:57 PM

No real way to tell unless you had a spring tester but it could by that the big impact of those metal things took some of the spring rate out of the left rear spring or maybe dismounted it. When you change the shocks check the springs and see if one is not set right or a rubber insulator is missing at the top.

How level does the rear of the car sit when you look at it from behind on level ground?

**LSCyaL8R** · 08-14-2009, 07:49 AM

The reason I point out springs as a possible culprit is because of this post here They claimed the springs were shot and replacing them greatly improved the harshness over bumps.... sounds like an SLP prokit is in my future??? I really don't want to lower much and 1" is probably the least I can lower while still putting better springs on. at less than 300 i'll probably take the plunge and do it. hopefully sometime before the end of the summer. I can't keep driving like this.

Question though. Is it really possible for springs to lose their spring rate yet not sag? my car seems to be at factory ride height ye something is deff amiss in the back of the car. I checked the spare and use air tools when i work on the car so things should be plenty tight. I've never had a prob with things coming loose and this bang is too harsh to be anything binding up either. the resulting bounce leads me to believe i certainly AM getting full suspension travel. When I say "bounce" i don't mean that the car bounces as though there was no damping. The car simply makes the long trip back up to normal height with no continuing resonance. pressing on the car when it's at rest will show it comes up once and stays there as it should.

***JC*** · 08-14-2009, 08:19 AM

Originally Posted by JaycenK

No real way to tell unless you had a spring tester but it could by that the big impact of those metal things took some of the spring rate out of the left rear spring or maybe dismounted it. When you change the shocks check the springs and see if one is not set right or a rubber insulator is missing at the top.

How level does the rear of the car sit when you look at it from behind on level ground?

My car sets level...

As for those metal things that was just an example I provided to describe how it only exsist on one side. It's been making this thud crash long before I drove over those metal things. I don't even have to be going fast I can pull into a parking lot or back out of a driveway at an angle and the dip between the highway and say the parkinglot is enough to cause the thud/smash sound. The odd thing is it never does it when entering from the left only the right. I can pass over a railroad track and it doesn't do it at any speed or even speed bumps. I can have the left rear drop off into a pothole and it doesn't do it but if the right rear drops off into a pothole boom there's that thud/crash sound. Obviously the right rear is maxing it's travel distance and smacking the bump stop this is what lead me to believe it must be the shock. The right isn't getting any dampening effect?

I plan on installing the rear shocks tomorrow and see if that fixes the problem?

**Blue28** · 08-14-2009, 08:26 AM

Have you tried swapping the rear left and right shock, springs or both?

**LSCyaL8R** · 08-14-2009, 09:40 AM

not a bad idea.... but i like using problems as an excuse to "make it all better"

When springs don't work i'll go buy LCA's when that doesn't work i'll get a new TA. then Panhard then swap the whole rear axle heh heh heh... something is bound to fix it right?

***JC*** · 08-15-2009, 02:44 PM

Okay, replaced old shocks with new ones much improvement over the OEM shocks. However, this did not cure the thud/crash noise. I inspected everything and could not find any suspesion parts lose or worn. Nevertheless, upon inspecting the wheel play I noticed that when pressure was applyed to the wheel it seemed to move. I found this a bit odd that the bearings would have that much play at the end of the axle shaft? I'm now wondering if it's not the wheel bearings? I can move the wheel slightly within the bearings enough that it can be seen. I would think that's more play than is permitted between the axle shaft and the wheel bearing?

Could this be the problem and cause of the thud/crash sound?