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Upstairs in the basement
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Discussion Starter #1
Since new I have had this noise coming from what I thought was the right rear of the car. Its sort of a grinding, rubbing, vibration kind of noise that you might hear if you had bad clutch packs in the diff or even a wheel bearing on the way out. But its not all the time, very intermittent. I cant even make it happen, but when it does happen I can almost make it continue. Its usually at slower speeds at lower RPMs with not much of a load on the car.

Last night I drove down to Atlantic City with a buddy (car tech as well) and my father in law. FIL sat in the back seat and said the sound was definitely coming from the LEFT rear. Hmmm I guess that it only seems like the right rear to me because of my listening position and the accoustics of the car. Anyway, I dont think its the rear or the drive train because its very intermittent and I can duplicate the conditions from when I have heard it before but the sound doesnt always happen. I would think that if it were a mechanical problem with a moving part that it would almost always make the same noise under the same conditions.

I have had the car up on the lift at the shop and I cant physically see any problem with the car. Of course I wasnt looking for any exhaust issues, but I will be doing just that the next time I take it to work. I have pretty much ruled out anything other than it must have something to do with resonance and the exhaust system is hitting something near the back end of the car, possibly where the pipes overlap (speaking of which, WTF sense does that make anyway?)

Just wondering if anyone else has this "noise" and if you have truly found out what it was.
 

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I know what you mean about being able to reproduce it. If you could get the same conditions but what are they? Have you thought about the brakes? Maybe the noise shows up more on bumps or a bumpy road?
 

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Upstairs in the basement
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Discussion Starter #3
Never during breaking, always at slower speeds (say 45 50 MPH and under) at lower RPMs with not much of a load on the car. Started out only showing up when going around a slight bend in the road to the left, like a long sweeping turn, but not just on turns, it did it entirely last night when going in a straight line.

There is no deceleration whine like you might expect from a rear going out and the noise is always with just enough pressure on the throttle to maintain the same speed as if you were just "floating" down the road.

I have had several rears go out on cars over the years, usually from too much HP until they blow up and I put a good strong replacement in. Heck the rear in my Z06 went out last year after I drove it to CA from NJ but that was a constant sound and always around tight turns. The clutch packs in it burnt up because I listened to a Corvette shop that said straight AMSOIL synth gear oil was fine. Well I figured they should know what they are talking about and it was my first IRS car so I listened. Well I should not have. Even in the IRS rears as long as its a GM rear and uses clutch packs for the POSI unit, you still need to put the GM additive in or else the clutch packs will burn up.

Anyway, not to get off on a tangent, unless its something just plain weird with this car, I dont think its the rear especially since the noise has been confirmened by a back seat passenger that its coming from the left side of the back of the car.

I thought it might be a brake dragging too, but again a dragging brake would show signs of wear, I dont see any and it always seems to happen when I am under slight slight acceleration as I described above.

It really seems to be a resonance of some sort. Oh and I checked my VIN, I am after the cutoff for the TSB on the diff mount bushings mentioned in the thunk in the trunk threads.

LOL I wish I could get someone to ride in the trunk and see what it sounds like and pinpoint exactly where its coming from.
 

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May I quote you on that?
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Shag Finger said:
LOL I wish I could get someone to ride in the trunk and see what it sounds like and pinpoint exactly where its coming from.
There's already too many folks in Jersey driving around with someone in the trunk. :gr_jest:
 

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Upstairs in the basement
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Discussion Starter #5
mistermike said:
There's already too many folks in Jersey driving around with someone in the trunk. :gr_jest:

LOL I hear ya, but I live the good part of Jersey....There is actually one area that doesnt have much crime, doesnt stink, the people dont talk like "Joisey" poeple and its not full of the rednecks from the "Deliverance" part of the state down south. I think its because I am right on I-95 and can actually see PA from my house :wall:
 

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Slight Vibration

Shag Finger said:
Since new I have had this noise coming from what I thought was the right rear of the car. Its sort of a grinding, rubbing, vibration kind of noise that you might hear if you had bad clutch packs in the diff or even a wheel bearing on the way out. But its not all the time, very intermittent. I cant even make it happen, but when it does happen I can almost make it continue. Its usually at slower speeds at lower RPMs with not much of a load on the car.

Last night I drove down to Atlantic City with a buddy (car tech as well) and my father in law. FIL sat in the back seat and said the sound was definitely coming from the LEFT rear. Hmmm I guess that it only seems like the right rear to me because of my listening position and the accoustics of the car. Anyway, I dont think its the rear or the drive train because its very intermittent and I can duplicate the conditions from when I have heard it before but the sound doesnt always happen. I would think that if it were a mechanical problem with a moving part that it would almost always make the same noise under the same conditions.

I have had the car up on the lift at the shop and I cant physically see any problem with the car. Of course I wasnt looking for any exhaust issues, but I will be doing just that the next time I take it to work. I have pretty much ruled out anything other than it must have something to do with resonance and the exhaust system is hitting something near the back end of the car, possibly where the pipes overlap (speaking of which, WTF sense does that make anyway?)

Just wondering if anyone else has this "noise" and if you have truly found out what it was.

I think your right about it being the exhaust. When I am heading in a down angle, like to get in a parking lot, I hear the "Sound". It will be interesting to hear if the 05's have the same "sound" coming from the rear of the car.

It's still an awesome car, I love it :)
 

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May I quote you on that?
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After a recent stop at Taco Bell, I got a strange noise from the back end.
 

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There was a noise in the back of mine. It was the exhaust. Nit sure if the same sound, but there is a little flat brace right at the end of the exhaust. Right before the tips. Well they didn't weld it to well or some how it ripped. So at certain rpms it would vibrate. So I just bent it up out of the way.
 

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Enjoy the trolls
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Make sure the dual exhaust tip is not rattling against any metal components from the part that suspends it. There is this red rubber thingy that buffers it from up above....



 

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Shag Finger said:
LOL I wish I could get someone to ride in the trunk and see what it sounds like and pinpoint exactly where its coming from.
There is a release lever to open the trunk from the inside. That's how my people get out.
 

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I too have the same problem. I have had my dealership look at it twice, but the only conclusion they came too was that this is "normal for this model". The problem is definately coming from the left rear end. I am going to take mine to another dealership this week as I am convinced that is it is not normal.
 

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I high pitch whine from the rear of GTO's is not uncommon. It usually eminates from the driver of the Ford or Ricer behind you that you just blew away and will stop after a short while as the distance between you increases. :)
 

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About a month ago, I have been getting a noise from the back end but it is different from yours. Anytime I go to sit in the car, get out, or drive over bumps or uneven rode, the rear end squeaks. It sounds like styrofoam(sp?) in the springs, but I was under the car today and didn't see anything. I'm going to try and put some lube on the anti-sway bar bushings as well as the strut rod bushings.. I don't know what it is but it is definitely suspension related.
 

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Captain Thread Killer returns
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Shag Finger said:
Just wondering if anyone else has this "noise" and if you have truly found out what it was.
too many beans can cause the noise from the backend.........
 

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Upstairs in the basement
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Discussion Starter #15
Dbluegoat said:
too many beans can cause the noise from the backend.........

LOL not!!!

Ok well its an exhaust noise. I found that the rear hangers at the tips really dont do much, the exhaust is almost completely suspended from the muffler hangers. There is almost no tension on the rear hangers, the rubber donuts are just floating on there.

Since I had the resonators cut out the noise is all but gone and when it does appear you really really have to know when to listen for it and what to listen for. If I hadnt heard the noise before and knew what to listen for I wouldnt even hear it now.
 
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