# rear clunking/clacking noise on 05 A4.........



## pctek (Jul 18, 2010)

I have a 05 yellow A4 gto with 47,000 miles on it from the first owner. Got a this past saturday me and wife looking to trade in my trailblazer for a muistang gt or cobra for myself, stopped at a chevy dealer and saw this and loved it.

It runs great all kinds of torque and power man. Anyways I hear like a clunking/clacking noise from the rear seems like from the middle rear I think. Seems like it happens often when your dealing with the different combination of let the gas pedal out and apllying it again and using the brakes and letting it go and pushing the gas down again. 

Like if I was to slow down to a crawl or complete stop and then release the brake and give it gas sometimes it will make that clunking noise like something has play and loose. 

Anyone have any info I need to know? Does changing the rear diff fluids help with clanking/clunking loose play symptons? Seems like that will help the common whine the diffs make on these cars right? Thanks


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## Falco21 (May 11, 2010)

you stated in the other post that you have the warranty. Just take it into the dealer and have them solve it. It could be a million and one reasons why its doing that. The best bet is since it is free, to let the dealer diagnose it for you. Best of luck :cheers


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## jpalamar (Jul 22, 2008)

Make sure to post the results when you get it fixed too! GM certified is a great thing.


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## GTO JUDGE (May 14, 2005)

Clunking and growling has been reported in the rear ends. I was a victim of it. The viscosity of the oil breaks down in time. Is this happening to you? If so >>

Internal clunking or growling from the rear diff:
http://www.gtoforum.com/f3/growling-clunking-noise-coming-rear-14102/


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## Poncho Dan (Jun 30, 2009)

I have it, maybe? I get a click-clack when I change gears, and can hear the diff loading and unloading, but I guess I'm used to it since my old RWD Pontiacs did that too.

It needs some fluid front and back, for sure... it's at 42K and I haven't touched it since I bought it.


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## pctek (Jul 18, 2010)

GTO JUDGE said:


> Clunking and growling has been reported in the rear ends. I was a victim of it. The viscosity of the oil breaks down in time. Is this happening to you? If so >>
> 
> Internal clunking or growling from the rear diff:
> http://www.gtoforum.com/f3/growling-clunking-noise-coming-rear-14102/


This is also for "PONCO DAN" so the more I drive it Im getting the feel of when its happening. When Im driving along in regular constant speed on streets or freeway I hear nothing wrong, even when going over rought bumps, pot holes whatever on the streets the car is going over them smooth and no clanking/loose play type noises.

This loose play clanking noise happens when you brake at low speeds basically and then if you let go of brakes and where to hit the gas then it do that issue.

Yea the gm certified is good but if its a basic diff oil change I like to do it myself since its not to expensive. I thought diffs issues will be only the whines, howles, but bad diffs or oils can really cause something that sounds like it has come loose with play which makes a clanking/clunking noise I dont get it. Thanks


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## pctek (Jul 18, 2010)

I think this saturday I might want to lift the back in of the car and see if I can see a issue, does anyone know spots in the back of car to lift with regualr small floor jacks? All I have is regualr size small floor jacks couple of them, floor stands thats it. Thanks


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## AlaGreyGoat (Jul 6, 2006)

SEE: GTO Lifting Locations.gif


(1) Suspension Contact Hoist Lifting Locations 
(2) Preferred Frame Contact Lifting and Jacking Locations 
(3) Spare Tire Service Jack Lifting Locations and Optional Vehicle Jacking Locations 
(4) Optional Floor Jack Lifting Locations


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## jpalamar (Jul 22, 2008)

pctek said:


> This is also for "PONCO DAN" so the more I drive it Im getting the feel of when its happening. When Im driving along in regular constant speed on streets or freeway I hear nothing wrong, even when going over rought bumps, pot holes whatever on the streets the car is going over them smooth and no clanking/loose play type noises.
> 
> This loose play clanking noise happens when you brake at low speeds basically and then if you let go of brakes and where to hit the gas then it do that issue.
> 
> Yea the gm certified is good but if its a basic diff oil change I like to do it myself since its not to expensive. I thought diffs issues will be only the whines, howles, but bad diffs or oils can really cause something that sounds like it has come loose with play which makes a clanking/clunking noise I dont get it. Thanks


It isn't your fluids. Part of buying GM certified used is that they change all the fluids/filters before you buy the car.


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## pctek (Jul 18, 2010)

jpalamar said:


> It isn't your fluids. Part of buying GM certified used is that they change all the fluids/filters before you buy the car.


Right I n otice the diff bolts where clean and looked recently removed. Like I said that clanking doesnt seem to be a diff oil issue like GTOJUDGE thinks it is.

SO I guess I'll investegate under the car. Thanks


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## GM4life (Mar 18, 2007)

Take it back to the dealer and have them check it out. If not check all of the cradle mounting bolts including the diff mount, exhaust hangers, driveshaft including the carrier in the middle of the driveshaft, brake calipers, suspesion bolts, wheel mounting, with the car in the air grab the wheel w/both hands and shake and CV shafts. Be firm when you check out things grab and shake take the palm of your hand and hit things. Don't worry you won't break nothing if you do then thats your problem


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## pctek (Jul 18, 2010)

GM4life said:


> Take it back to the dealer and have them check it out. If not check all of the cradle mounting bolts including the diff mount, exhaust hangers, driveshaft including the carrier in the middle of the driveshaft, brake calipers, suspesion bolts, wheel mounting, with the car in the air grab the wheel w/both hands and shake and CV shafts. Be firm when you check out things grab and shake take the palm of your hand and hit things. Don't worry you won't break nothing if you do then thats your problem


Thanks for the tips I'll report back tommorow give you guys the heads up.


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## pctek (Jul 18, 2010)

No sure if the noise I hear is due to this what I found when I lefted my 05 gto on a lift. The flex disc that connects the drive shaft to the tranny up fron location is cracked and loose. Since I have the gm certified 12,000 mile or 1 year warranty I assume they will fix it rigght?


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## pags20 (Dec 26, 2009)

I think what you have is a Backlash/Clunk issue. Excessive backlash clunk under acceleration or deacceleration can be caused by any of the follow.
1. Worn differential pinion shaft
2. Worn differential pinion and/or side gears
3. Worn thrust washer
4. Excessive clearance between differential side gears and or bore in case
5. Excessive drive pinion and ring gear backlash

The repairs are probably not cheap but it would be wise to have a Tech. check it out. These rear ends are not an easy fix for your average backyard mechanic.
Good Luck


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## pctek (Jul 18, 2010)

pags20 said:


> I think what you have is a Backlash/Clunk issue. Excessive backlash clunk under acceleration or deacceleration can be caused by any of the follow.
> 1. Worn differential pinion shaft
> 2. Worn differential pinion and/or side gears
> 3. Worn thrust washer
> ...


Thanks for the tip maybe I'll print this and show the service writer so they have some tips also to troubleshoot the issue.


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## street_hurter (Aug 2, 2010)

*Problems!!!!*

im new to the forum so i thought maybe you guys could help. i have a 05 A4. 37k on it. i have a clunking noise too on stop and go. usually at low speeds when taking off but clunks and the stop too. im thinking U-joints but not sure. any ideas? its driving me nuts. another weird thing is just one day my front passenger tire started rubbing the plastic inside the wheel wells. any help guys?


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## GM4life (Mar 18, 2007)

street_hurter said:


> im new to the forum so i thought maybe you guys could help. i have a 05 A4. 37k on it. i have a clunking noise too on stop and go. usually at low speeds when taking off but clunks and the stop too. im thinking U-joints but not sure. any ideas? its driving me nuts. another weird thing is just one day my front passenger tire started rubbing the plastic inside the wheel wells. any help guys?


I would start by changing the rear end fluid. That should get rid of the clunking that you are having. The RF tire rubbing the plastic is normal for some. My 18's do it not my stock 17's. I would also check your radius rod bushings too.


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## street_hurter (Aug 2, 2010)

Got band new fluids in it. Actually just changed all of them except the trans. I do have aftermarket blacked out TSW 18s on there. I may check that bushing. We did get a little bit of water over here like 2 weeks ago. I was driving and hit a dip to where water was up to my headlights. Flooded out and quickly pushed it out of the dip. After 3 days of sun and fans it was alright... dont know if it has anything to do with it.


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## street_hurter (Aug 2, 2010)

For the rear diff fluid i just realized i put in 75w.... ewwwwww damn. Just found out we need the 85w correct? If so im going to go ahead with the royal purple... already has the additive


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## badgoat91 (Jul 13, 2009)

ya the clunking happens to most of the a4's, including mine, but some of the noise your hearing may be coming from the transmission, i have the alldata program and theres a bunch of service bulletins on transmissions bangin hard when they shift with 4l65e. u may think its the diff but im skeptical. i put in a different diff and the same thing happened.


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## pctek (Jul 18, 2010)

badgoat91 said:


> ya the clunking happens to most of the a4's, including mine, but some of the noise your hearing may be coming from the transmission, i have the alldata program and theres a bunch of service bulletins on transmissions bangin hard when they shift with 4l65e. u may think its the diff but im skeptical. i put in a different diff and the same thing happened.


See my clunking noise also happens at low speeds with stopping and going, even going reverse from my garage will do it. to me it seems to be drive train related but not the A4 transmission though, for one the tranny shifts fine at low speeds and freeway high speeds as well. 

The issue jsut gots to be from the front rubber driveshaft (DONUT) coupler to the diff area. I just dropped my car to a dealer that I live next door to  and I'll report here what the fix is so maybe can help the other guy here reporting same issue as me. Thanks


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## street_hurter (Aug 2, 2010)

cool appreciate it buddy. i did put the royal purple in and it seemed to help it a little bit. but ive also heard the tranny mount is notorious for going bad in A4s and the M6s. could be the tranny bangin when the torch is applied. lol. looked into the pricing, they are about $25. any ideas on how hard they are to change?


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## pctek (Jul 18, 2010)

street_hurter said:


> cool appreciate it buddy. i did put the royal purple in and it seemed to help it a little bit. but ive also heard the tranny mount is notorious for going bad in A4s and the M6s. could be the tranny bangin when the torch is applied. lol. looked into the pricing, they are about $25. any ideas on how hard they are to change?


Your talking about the rubber driveshaft coupler closest to the tranny right? Also called rubber disc right? If so I think its easy, the hard part is lifting the car without shop lifts  so if you can get undeneath car comfortably then all you got to do is remove some bolts and remove old rubber coupler and install the new one. Just to be sure theres no issues just align the drive shaft bolt holes just like it came out to the new one when connecting to the tranny side.


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## pctek (Jul 18, 2010)

Well I got a call from service writer at dealer right now telling me yes they do see the issue that I told them about waht I found last week that the front rubber driveshaft flex disc is cracked needs to be replaced, but they didnt hear or feels the clunking issue I told them about.

He said lets replace the flex disc and see if that fixes the issue, so I ok hope that simple fix fixes the clunking issue if not this time I have him or a mechanic go for a little ride to hear it.


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## pctek (Jul 18, 2010)

With all this time and post's I submiited here I forgot to mention a detail to why or when the drive train clunking occurs. 

Well the clunking issue only happens when the car is warm and hot from driving it so usually like in 10-20 minutes, but when its cold its all quiet. So i was thinking today at work, and said hmmm within the drive train the diff gear oil is the only thing that can be temperture related of having whatever issue it can have. 

So I told the dealer today that has my 05 a4 gto and I told then about this and also about a slight whining noise the diff makes from 40 mph to 55 mph, so I think hope they start with the basics and change the diff oil and put some friction modifier and see if that takes care the issues if not could be the diff needs to be replaced we'll see.


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## GM4life (Mar 18, 2007)

pctek said:


> With all this time and post's I submiited here I forgot to mention a detail to why or when the drive train clunking occurs.
> 
> Well the clunking issue only happens when the car is warm and hot from driving it so usually like in 10-20 minutes, but when its cold its all quiet. So i was thinking today at work, and said hmmm within the drive train the diff gear oil is the only thing that can be temperture related of having whatever issue it can have.
> 
> So I told the dealer today that has my 05 a4 gto and I told then about this and also about a slight whining noise the diff makes from 40 mph to 55 mph, so I think hope they start with the basics and change the diff oil and put some friction modifier and see if that takes care the issues if not could be the diff needs to be replaced we'll see.


I had that same problem twice when the fluid got warm it stated clunking. Yes the fluid needs to be changed but thats a bandaid it will come back. With the whining a fluid change won't help it, its worn gears that wasn't set right. Common problem with these diffs. You need a new diff.


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## 87GN06GTO07IRL (Aug 10, 2009)

Two piece drive shafts make more noise than a one piece. Sounds like that is what most are describing.


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## GM4life (Mar 18, 2007)

One piece driveshafts make more noise than two piece.


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## pctek (Jul 18, 2010)

street_hurter said:


> cool appreciate it buddy. i did put the royal purple in and it seemed to help it a little bit. but ive also heard the tranny mount is notorious for going bad in A4s and the M6s. could be the tranny bangin when the torch is applied. lol. looked into the pricing, they are about $25. any ideas on how hard they are to change?


Ok got my goat back last evening, service writer calls and says its all good. They ended up removing the diff cover and the gears looked good, there was no broken peices within the old gear oil etc.

So they put in fresh gear oil and friction modifier and so far the clunking noise is gone, so definelty that noise was from the Diff. But the word "CLUNKING" is refered to other issues within a car so just make sure it is drive train related and most likely it will be the diff. Specially if the clunking feels and sounds like its from the rear middle of car.

Heres the part #'s they used to put in fresh oils:

88862624
89021809

This is the front rubber driveshaft coupler joint: 92149040

Also does anyone know what this means not sure if its a part or not:

PO#87550 STOW

Thanks


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## HP11 (Apr 11, 2009)

That last entry looks like the purchase order number and perhaps someone's name.


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## pctek (Jul 18, 2010)

HP11 said:


> That last entry looks like the purchase order number and perhaps someone's name.


Ohh ok thanks...

Also forgot one detail in determing if its a diff oil issue, is my gto issue was when the diff was cold the clunking noise was not there, only after about 10 to 20 minutes of driving the clunking noise started, so right there raises a flag saying whats in the drive train that is can change symptons when the heat changes one thing is oil, so eveyone with this type of issue realize if it does not happen when the diff is cold.


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## 87GN06GTO07IRL (Aug 10, 2009)

GM4life said:


> One piece driveshafts make more noise than two piece.


Care to elaborate?


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## GM4life (Mar 18, 2007)

06gtoin216 said:


> Care to elaborate?


Thoes rubber couplers in the driveshaft really do work. I driven 6QTS car after he had a single piece driveshaft put in. I tell ya, the hermonics did come into play.


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## 87GN06GTO07IRL (Aug 10, 2009)

GM4life said:


> Thoes rubber couplers in the driveshaft really do work. I driven 6QTS car after he had a single piece driveshaft put in. I tell ya, the hermonics did come into play.


Gotcha. I completely agree with this statement but i was referring to the more audible clunk associated with a two piece shaft when going in and out of gears.


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## GM4life (Mar 18, 2007)

06gtoin216 said:


> Gotcha. I completely agree with this statement but i was referring to the more audible clunk associated with a two piece shaft when going in and out of gears.


If your talking along the lines of the rubber coulplings having alittle more flex? I can possably see that. And I tell you why I can see that: when I was torquing down my crank bolt you had to take up the slack of the rubber donuts first before the actual torque was applied to the bolt. Most drivetrains have some slack in them, it seems to be alittle worse with manual cars. The loud clunk will usally be the diff.


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