I had the dealer install the TRD Rear Sway Bar and a few days later I have a loud clunking noise from the rear. To make the noise one must simply drive the car in a parking lot and gently rock the steering wheel back and forth.
The radio need not be off, by the way, it is that loud. Going over speed bumps also makes it happen. Not sure if it is the TRD Sway Bar specifically but my wife has a unmodified tC and no noises from her car.

EDIT: To avoid any confusion here, I ordered the car with the sway bar preinstalled (hence underlined portion above). I did not buy the car without it and take it back to have it added.
Not sure if that would have made a difference where it was installed but I just thought I would clarify that point.

 

Sounds like the either one of the bar mounts or end links are loose.

 

I got under the car, but it was still on the ground so under load, and grabbed the sway bar and tried to shake it and other things but couldn't figure out what was loose. If you push the back of the car side to side you can make the noise and I can feel it holding on to various suspension components but still can't determine the origin.

I heard that this is a 'common problem' with the tc from the service department. But they don't know if my car has the same problem as other cars they have seen. I was just wondering if anyone else had this problem and what the fix was. Thanks.

 

I installed mine myself and haven't had any noises from the rear of my car. Sounds like either one of the parts they installed was defective, or they screwed up the install.

The 'common problem' line sounds like BS.

 

I read your article on the sway bar install, Jason, very nice. It seems like a very straightforward job so how they could have screwed it up is beyond me. Nothing else has to be unbolted but the bar, right? When the car is at rest is there any tension on the endlinks? If the bar is loose I could not get it to move no matter how hard I yanked on it in all directions.

About the 'common problem', they said if my car has the same problem as those other ones they have seen, then they know how to fix it and it is a relatively fast procedure. When I get my car back I will post exactly what they did to fix the problem.

 

Right, but they might have unbolted the exhaust ir taken it off the hangers to make getting the bars in and out easier. There's no real tension on the endlinks unless one side of the car has weight on it but the other side doesn't. If you push up and down on the rear bumper the bar will just move up and down.

Possibly meaning "We've installed these before and did a poor job/forgot to tighten something/didn't grease the bushings/etc. so we know how to fix our mistake."

 

Or maybe the shocks are tightened down, or the springs aren't seated properly.

I wouldn't jack the car all of the way up, but partially, and check to see if everything is tightened down properly and seated correctly.

 

Ditto

 

The exhaust moves around without any noises both when shaking the muffler manually or rocking the car side to side.

Thanks for the suggestion but when I get the car back I guess this will be pointless and I live in an apartment complex so wheeling a jack out to the parking garage may be a pain :D.

 

Just got a call from the dealer. Sure enough, they said the sway bar was loose. I asked him why it was loose since I bought it with the car preinstalled. He said scion accessories are installed at the 'vehicle processing center' not by the scion or toyota dealership.

Thanks for all the quick replies, I really appreciate your support. Now hopefully I can get back to driving the car.

 

Cool deal, glad it wasn't anything serious.