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Discussion Starter #1
Hey guys,

Well to make a long story short, there is this annoying as hell knocking sound that comes from the back of my car. It hear it every time I hit a bump.

So about a month and a half ago, I brought it to my mechanic and he said he checked every component in the back of my car to make sure every thing is tight and he said he doesn't know where this sound is coming from. At first he said it might be the "links" after checking them out they were fine.

So I then decided to bring it to another garage and over the phone he said that it might be my "plates". Something to do with suspension or shocks im not too sure what he said. i brought it in, he took if for a test drive and hear the sound. He lifts my car up and plates are fine. once again he checked for any loose parts and couldn't find anything.

I then decided to bring it into my GM dealer (last resort since i don't wanna pay outta my ass). They also cant find the problem.

I am freaking out, the sound is driving me crazy. Feels as if im driving a shit box....I don't know what to do or where to go. I have a 2005 G6 with 103,000 km.

Have any of u guys have had a similar problem?
 

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I haven't had this problem on my G6, but I had something similar on my Monte Carlo. Does it sound like it is rattling when you hit even the slightest bump?

For my Monte Carlo, it was bad strut bushings. The mechanic I go to, kept tightening them down but it did nothing. The whole sleeve was worn out. Not sure of the suspension set up in the G6, but might be something to look at.
 

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Discussion Starter #3
well if im driving on a highway or at a pretty fast speed, i barely hear the knocking. its when im driving in the city. Its not rattling, its more knocking. To be more exact, it sounds like something is loose.
 

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Discussion Starter #7
Get a friend to drive while you hang in the back seat, leave on of the back seats down. You might be able to narrow the area like that.
Ok so I tried doing what you suggested and it seems to be coming from near both wheels. I can also feel the knocking more from the back. I just went on a road trip to Toronto this past weekend and my buddies didnt hear or feel anything from the back. Seems to me as if im the only one that hears that noise.

I'm gonna try going back to the dealer and getting my strut bushings checked. If there is nothing wrong, im gonna push my damn car off a cliff lol
 

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Ok so I tried doing what you suggested and it seems to be coming from near both wheels. I can also feel the knocking more from the back. I just went on a road trip to Toronto this past weekend and my buddies didnt hear or feel anything from the back. Seems to me as if im the only one that hears that noise.

I'm gonna try going back to the dealer and getting my strut bushings checked. If there is nothing wrong, im gonna push my damn car off a cliff lol
You could try to jack up on side at a time, right before the wheel come off the ground try shaking it. Put a jack stand under there and look around. There's no telling what it could be. Another idea, take it to a body shop, they are the ones who fix this kind of stuff, not dealers(if you aren't the original owner it may have had a fender bender in the past.)
Just brain storming with you.:confused:
 

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Discussion Starter #9
You could try to jack up on side at a time, right before the wheel come off the ground try shaking it. Put a jack stand under there and look around. There's no telling what it could be. Another idea, take it to a body shop, they are the ones who fix this kind of stuff, not dealers(if you aren't the original owner it may have had a fender bender in the past.)
Just brain storming with you.:confused:
Well I purchased the car in 2006. The car had only 17000km. I got a free carfax report and there was no accidents in the past. Well nothing registered.

I've had the car for going on 5 years now, I had my back bumber replaced twice due to a fender bender. The 2nd time happened over a year ago, and this knocking sound started a few months back. When i brought it over to the dealer, they said they made sure everything was in place and tight.

Man seriously this car is giving me headaches......I've learned to deal with my steering knocking sound, and now the back...lol

Anyways, later on during the summer i'll bring it to my local garage and tell them to take apart the back of my car so they can fix it. However bringing my car to a body shop aint such a bad idea. Hope they are able to pinpoint where the sound is coming from.
 

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2006 G6 GTP
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It's the SWAY BAR BUSHINGS

I had this problem about a year ago. It almost sounded like a horse galoping down the road in the rear end. It took me awhile to figure it out. I had my wife rock the car side to side while I looked for the source of the noise. It was a LOUD knocking noise that almost seemed to come from the trunk area where it was amplified the most. Then I got underneath the back and just felt around for vibration only to find that my sway bar bushings were SO wore out that there was almost a half inch gap inside the bushings. I ordered the replacement parts, went to put em in and 3 out of the 4 bolt heads twisted off that holds the bushing bracket in place. (I was totally pissed by now :mad:). I ended up having to drill out the tiny bolts for the brackets and re-tapped the new threads and put Grade 8 replacement bolts in.:bash: It was a mess and total hassle to do this, BTW. After dropping the rear end subframe to get enough room to do anything, the new ones were installed, done. And now, she rides as good as new...:):bravo::D
 

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Get under the car when its cold, and try to wiggle around the muffler, Maybe a hanger broke and it's tapping the trunk or bumper?

Also behind the rear bumper cover is a plastic energy absorber, maybe it was damaged or not installed properly and knocks around. If you reach up between the bumper and the muffler you can feel it. I would just just kind of grab it and move it around a bunch and see what it sounds like. I thought mine was squeaking real bad so I pulled it off and put some rubber strips in so it can barely move.
 

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2006 G6 GTP
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Does it make the noise when u rock the car side to side? Or does it make the noise when u bounce on the bumper? My noise was only when i rocked the car side to side and had almost a hollow knock sound to it.
 

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Discussion Starter #13
Does it make the noise when u rock the car side to side? Or does it make the noise when u bounce on the bumper? My noise was only when i rocked the car side to side and had almost a hollow knock sound to it.
It's only when I drive over bumps. It's almost as if something is loose. to be honest I never got it fixed. 3 different mechanics said its not worth the money and to endure the sound.

All 3 have said its bushings but it could be in different locations. I'm actually going to sell my car this summer so I'm debating if I should fix it or leave it as is. Hope potential buyers won't get turned off by that sound...
 

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2006 G6 GTP
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Do this...

Start from here:
Jack the car up so that it's off the ground, starting with the front end. Wiggle each tire from side to side, left to right. If it is loose, it will make a clunking noise. If it does make the clunking sound or something similar, look on the inside at the ball joint(the joint with a rubber boot on the bottom-side of the hub). If the ball joint is bad, u will be able to see sloppy movement+reproduce the clunky sound that u hear by doing this. They are fairly easy to replace, but they can only be purchased with the whole control arm assembly(comes with new arm bushings too). It only takes 3 bolts to remove and install. Place a jack under the engine(using a piece of wood for cushion). Jack the engine up just enough to remove the lower engine mount. Remove it. Then unbolt the control arm (after disassembling the caliper, caliper bracket and axle nut, etc). Just ask if u have any questions.

Here's Advance Auto's links

Right side:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Suspension-Control-Arm-Dorman---OE-Solutions_21299161-P_2071_R|GRP60005_____

Left side:

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Suspension-Control-Arm-Dorman---OE-Solutions_21299160-P_2071_R|GRP60005_____
 

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Discussion Starter #15
Start from here:
Jack the car up so that it's off the ground, starting with the front end. Wiggle each tire from side to side, left to right. If it is loose, it will make a clunking noise. If it does make the clunking sound or something similar, look on the inside at the ball joint(the joint with a rubber boot on the bottom-side of the hub). If the ball joint is bad, u will be able to see sloppy movement+reproduce the clunky sound that u hear by doing this. They are fairly easy to replace, but they can only be purchased with the whole control arm assembly(comes with new arm bushings too). It only takes 3 bolts to remove and install. Place a jack under the engine(using a piece of wood for cushion). Jack the engine up just enough to remove the lower engine mount. Remove it. Then unbolt the control arm (after disassembling the caliper, caliper bracket and axle nut, etc). Just ask if u have any questions.

Here's Advance Auto's links

Right side:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Suspension-Control-Arm-Dorman---OE-Solutions_21299161-P_2071_R|GRP60005_____

Left side:

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Suspension-Control-Arm-Dorman---OE-Solutions_21299160-P_2071_R|GRP60005_____

The sound is coming from the back of my car. The front is ok. I wish I could record the sound to make you guys hear it. It's as if there is something loose. Those mechanics seem to think its worn out bushings. However they said it could e in several places.

Is there any way for me to check those bushings without removing any parts?? Where and what do I look for?
 

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2006 G6 GTP
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Ok. I had this prob on my GTP. Have someone rock the car side to side. Crawl underneath the back and put ur hand on the sway bar(away from any pinch spots). Can u feel the vibration of the clunk noise when u touch the sway bar? If u can, chances are that u have worn out sway bar bushings. Just follow the bar to each side to where it appears to have a bracket clamp with 2 bolts holding it. Your sway bar bushings should be in between the sway bar and the bracket clamp on each side directly under the trunk/seat area(underneath, bolted to the rear subframe). Just ask if u have questions.
 

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Discussion Starter #17
I'm sorry for being so clueless but where is the sway bar in the back?? What am I looking for?? Would you happen to have a picture that points out where I should be looking??
 

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I have the same problem,dealership told me it was the shocks. I replaced a number of things on the car, struts, shocks, brakes on all four corners, front sway bar links, inner outter tie rods, and front sway bar bushings, took car for test drive, front was nice and tight/solid (big improvement) still clunking in the rear though. took it in for the alignment, no go, need front ball joint, but they did notice the rear sway bar bushing is totally worn along with the link. this is very common cause of clunking noises from the rear on g6's
 

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So ordered 2 front control arms/ball joints from rock auto $109.99 ea. and ordered the swaybar kit from gm parts direct $70.78 hopin to put in next weekend (workin this weekend to pay for parts), will post results as soon as it's done
 

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Double check if the spare tire in the trunk isn't loose, i had a prob like that before and it was my spare tire wasn't bolted tight to the chassis how some cars have it and that's what was making the knocking/clunk noise.
 
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