rear clunking noise caused by torsion bar bushings

[vergil]

Hi guys I have a manual 2012 gt with koni yellow's, steeda sports, whiteline adj. upper and lower control arms, j&m adjustable pan hard bar and after doing all these changes car started to make a clunking noise from the rear. I took it to the dealer and it took their 2 days to figure out that it is the torsion bar. I see lots of people posting about this clunking noise, so it maybe be the same situation. Anybody knows how to fix this? Here is the complete explanation from the dealer:

"Found that the torsion bar from above diff is now angled thus the bushings are too tight and this making a clunk when in reverse and forward under acceleration."

 

[86Fbody]

I don't see how that could be causing the noise since the only way that would twist is if the body twisted which it shouldn't have. When does the clunking occur for you, in between shifts or while going around a corner slowly?

 

[vergil]

between shifts when you accelerate when it is decelerating you can hear it really loud when you press the clutch

 

[vergil]

it is coming from the driver side actually somebody hit it from the driver side last year and the door,whole rear panel and bunch of things were replaced by the dealer which cost around $8000.do you think that maybe that's the reason?I could hear it before but it wasn't this loud, it got worst after putting lower control arms.

 

[86Fbody]

Did it only start occurring after putting the Whiteline UCA on? Could just be gear lash.

 

[vergil]

It got worst after putting the lower control arms. Whiteline said they never heard such a problem before

 

[86Fbody]

Did you make sure the rears lined up with the originals before putting them on, did you get a rear and front alignment done?

 

[vergil]

yes everything done by a mustang shop here in Orlando including alignment and pinion angle adj.
The problem is nobody knows what torsion bar is everybody thinks it is the sway bar but it is not. They are two different things.

 

[Charliesgramps]

There is no "torsion bar" as part of the 3-link suspension. The only bar under torsion (twisting force) is the sway bar and that should only be during cornering.

Not sure what the dealer is talking about. The "bar" they are describing could only be either the UCA or the Panhard bar.

By chance, does your car have a the track pack or Recaro options? If so, it could it be the Torsen differential making the noise you describe. With all the higher durometer bushings, you may be hearing what is normal noise from it.

 

[vergil]

no it is the base, I asked them several times and they said it is the torsion bar.

 

[vergil]

View attachment 16433

this is the pic.

 

[draxxus131]

the picture is not working, says it is invalid. Really thoroughly check the rear endlinks for the sway bar.

 

[vergil]

I just tried to open the pic and it is working. I know sway bar end links are common problem for these cars and checked them several times it seems that's not it plus would they make noise when you are going straight? Perhaps dealer was trying to say pan hard bar?

 

[86Fbody]

1. you might have attached the picture and had the link pointing back to your machine instead of someplace like IMGUR or the like. B. I think what OP might be talking about is the "chassis" brace that goes above the PHB, correct me if I'm wrong.

 

[vergil]

thanks for all replies guys I will know for sure tomorrow and will take more pics if I can.

 

[vergil]

It was lower control arms that was causing the noise removed both upper and lower control arms put the stock ones back on and the noise is gone. They were both whiteline, adj. upper and lower control arms. Thanks to everybody for comments and help.

 

[Highway Star]

UCA not a Tortion bar.

It was lower control arms that was causing the noise removed both upper and lower control arms put the stock ones back on and the noise is gone. They were both whiteline, adj. upper and lower control arms. Thanks to everybody for comments and help.

It was your upper control arm that made the clunking sound not you lower. This is a common problem and is experienced by anybody that gets an aftermarket upper control arm no matter what brand. And an upper control arm is not a tortion bar I am pretty sure.

 

[768MPH]

Are there any UCAs that do NOT cause noise?

Would applying dynamat above and below UCA mount absorb the vibrations?

I applied dynamat from the top and bottom of my trans valley when installing my MGW. Quieter than stock shifter. NO noise.

 

[86Fbody]

Are there any UCAs that do NOT cause noise?

Would dynamat above and below UCA mount absorb the vibrations?

I dynamat the top and bottom of my trans valley when intalling my MGW. Quieter than stock shifter. NO noise.

Probably not, your increasing the rigidity to the rear which is also increasing the amount of NVH transmitted through the car.

 

[vergil]

It was your upper control arm that made the clunking sound not you lower. This is a common problem and is experienced by anybody that gets an aftermarket upper control arm no matter what brand. And an upper control arm is not a tortion bar I am pretty sure.

No Sir I already had the clunking noise after installing the lower control arms, upper control arm was installed a month later which is probably the reason for the whining noise from the back. I got them both used from the market section on this forum so I don't want to blame anyone until I completely figure out what the problem is. That torsion bar idea came from the dealer I believe they meant the Panhard bar and they didn't want to waste their time on a modified car.