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Loud knock and rattle from rear side wheel area

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Old 08-26-2017, 01:06 AM
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Default Loud knock and rattle from rear side wheel area

Hi everyone! I tried searching for a previous thread but I couldn't find anything specific to this problem. My son has a 2004 Crossfire and noticed some rattling and a loud knock coming from the rear end of the car on the right side. We checked all the plastic, that wasn't it. So I had a friend crawl into the back and we went for a ride. He heard and felt the noise coming from under the center divide toward the back of it near the wheel well. When I went over a rough spot in the road, there was a loud know with a little rattling. I wanted to start here for some advise before tearing the back of his car apart or taking it to a shop.

Thank you for any information provided!!!

Greg
 
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Old 08-26-2017, 07:48 AM
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Default Re: Loud knock and rattle from rear side wheel area

Most likely a broken sway bar mounting tab.
 
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Old 08-26-2017, 08:45 AM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by ala_xfire
Most likely a broken sway bar mounting tab.

Plus 1, there are a number of XF's that have the weak rear stabilizer bar mount breaking. Check this before anything else.

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Old 08-26-2017, 03:09 PM
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Default Re: Loud knock and rattle from rear side wheel area

Thank you so far for the ideas! Keep em coming! I took it to a small shop and the mechanic suggested to look at the bearings or the rear differential. I don't thing it's either if those but I'm open to anything. Thanks again!
 
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Old 08-27-2017, 10:18 AM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by GregJ
Thank you so far for the ideas! Keep em coming! I took it to a small shop and the mechanic suggested to look at the bearings or the rear differential. I don't thing it's either if those but I'm open to anything. Thanks again!

You didn't tell us if you checked the stabilizer bar mounts. Try to eliminate things suggested before going on. Let us know the results so we all can move on.

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Old 08-27-2017, 11:20 AM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by GregJ
Thank you so far for the ideas! Keep em coming! I took it to a small shop and the mechanic suggested to look at the bearings or the rear differential. I don't thing it's either if those but I'm open to anything. Thanks again!

Don't go back to that mechanic! If the diff is bad it'll howl like a Banshee or grind terribly and it's dead smack in the middle! I think the previous responses are a good place to start, plus check the suspension mounting points for worn bushings or loose bolts.
 
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Old 08-27-2017, 04:49 PM
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Default Re: Loud knock and rattle from rear side wheel area

This is what you would be looking for :

 
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Old 09-03-2017, 10:10 AM
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Default Re: Loud knock and rattle from rear side wheel area

Mine had a similar noise and I could find nothing underneath.
It turned out to be the tailgate - I adjusted the stops and noise gone.
It's odd how noise travels around cars, as I was utterly convinced it was coming from underneath!!
 
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Old 10-17-2017, 09:21 PM
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Default Re: Loud knock and rattle from rear side wheel area

Funny I had the same issue. Turned out to be the carrier bearing that holds the driveshafts together. Weird that it only happened when I put a load on the driveshaft....like giving it a more gas than I should...Weeee.
 
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Old 02-06-2018, 04:25 PM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by ala_xfire
Most likely a broken sway bar mounting tab.
thank you ala_xfire! That was it! I had them remove the sway bar for now.
 
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Old 01-04-2020, 12:14 PM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by ala_xfire
This is what you would be looking for :


It happend to me too.
 
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Old 01-05-2020, 09:42 AM
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Default Re: Loud knock and rattle from rear side wheel area

I’m really curious as to what was required to correct this

Please share any details
 
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Old 01-05-2020, 09:46 AM
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Default Re: Loud knock and rattle from rear side wheel area

Sorry I should have been specific.

Please share details associated with Correction to the sway bar mounting tab.
 
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Old 01-05-2020, 10:27 AM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by UrbanE
Sorry I should have been specific.

Please share details associated with Correction to the sway bar mounting tab.
See the thread ‘ Rear sway bar brackets cracking’.
Zip439 shows one fix, maybe he can report on its success.
I think it needs new brackets welded to a doubler plate inside the car, anything else is just a fix and no better than the OEM design. It looks like some failures ripped the bracket away with a piece of the floor attached to it.
 
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Old 01-05-2020, 10:53 AM
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Default Re: Loud knock and rattle from rear side wheel area

agreed, 1/4" to 3/8" steel plate on the other side of the pan to bolt to.
Drill it and tap it, bobsuruncle
 
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Old 01-06-2020, 10:42 AM
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Default Re: Loud knock and rattle from rear side wheel area

Originally Posted by onehundred80
See the thread ‘ Rear sway bar brackets cracking’.
Zip439 shows one fix, maybe he can report on its success.
I think it needs new brackets welded to a doubler plate inside the car, anything else is just a fix and no better than the OEM design. It looks like some failures ripped the bracket away with a piece of the floor attached to it.
I've been running around now with the H&R sway bar for a little over a year on the reinforcements I made to the rear sway bar brackets. Both sides are doing well. I like the method I used with the nutserts and panel adhesive best. The metal to which the brackets are welded is very thin. It sets under the fuel tank. So doing new welding there is difficult.
 

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