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Hunkerin Down
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Discussion Starter #1
when i drive it, at times, Its like loose then it Hooks up almost like its a slip then a clunk , But its not actually a slip I can tell by the engine RPM's.. i complained to my dealer they keep insisting its "normal"

Its Almost as If The Torque Converter, I dont know this, its what I think,
Like its not engaged and your in a way not exactly free wheeling, not a locked TC, then when you gas it, it slams into gear, But it doesnt make alot of sense because it seems like the noise is coming from the Differential.

Its really Hard to explain, any idea's guys? COuld it just be the clutches in the LSD acting up ?

I myself have never had an automatic that made so many noises, but i've never had a performance car either, Oh and my last car that was an Auto had a TH350 in it...

Thanks.

Diceman
 

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Unregistered User (dont tell)
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Does it feel like someone is squeezing something inside the transmission then releasing it and you slingshot away? I would describe this feeling as that of a disk brake being moderately applied then rapidly released. If so, I believe it is TM you are experiencing. I have experienced this a number of times with my car until I tuned out TM. Since then, it has never happened again.

Edit: I just re-read that there were lots of noises. I never experienced a lot of noises; just the occasional clunk of the transmission seemingly dropping into gear.
 

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Hunkerin Down
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Discussion Starter #4
I Have TM removed, it mostly does it when rolling along,coasting like when you slow down to take a corner then Light throttle coming out of the corner then a Clunk, for the split second before the "clunk" it feels like well almost like your not in gear, but you are.

Does this make any sense?

I wish it happened all the time so i could get it checked out.

Diceman
 

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I have a clunk when slowing down and then accelerating through a corner. The clunk is driveshaft/rear diff. Not sure on how to adjus/overcome this though. The dealer always say "thats suppose to happen".
 

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iamdiceman said:
it feels like well almost like your not in gear, but you are.

Does this make any sense?

I wish it happened all the time so i could get it checked out.

Diceman
I have the same thing happen from time to time but definately with out the clunk.
 

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Hunkerin Down
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Discussion Starter #7
maybe something is loose with one of the mounts or something back there, If i had a floor jack and a driveway i would crawl under there right now, and check, Since its warranty'd if it just breaks in 1/2 fine, but its just scary at times since its my DD.
 

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2004 Pulse Red A4
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Every once in a while, when I take off from a stop, the car is kind of sluggish for a half-second then something grabs or locks up and the car takes off. It's kind of like it's starting out in "first and a half" gear. Anyway it doesn't happen often and I don't have time to mess with it. Tranny fluid looks good. I don't hear any clunk noise from it.
 

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Meh, my jet is faster...
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286 Posts
Mine has just recently started doing this too! ^^^^^^^^
Then I got the grinding/clicking/clacking noise from the rear end around turns in town, and occaisionally when changing lanes at slower speeds. Seemed to only happen after a longer road trip...say greater than 30 miles.

History: Car is 20,530 miles young. Changed rear dif fluid around 3K miles to R/P 85-140....been there ever since. No probs. Last December had a strange rear-end misalignment issue that happened suddenly, over the course of a few days. Completely fried two rear tires 'cause the alignment was waaaay out of whack. Recently changed the dif fluid again because of this strange feeling/noise after a trip from MS to OK....used R/P again. Didn't make a difference. FInalyl took to dealer today...they'll see me tomorrow.

They think it's a fluid thing...I say it's an alignment thing. Could be a little of both...We'll see.
 

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Meh, my jet is faster...
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Welp, they changed the fluid last week, and apparenty put the wrong stuff in. Evidently there is a new oil requirement for our difs now, but nobody seems to have the stuff. Anyway, the noise got worse after the change, so back to the dealer it went. I pressed the whole, "Oil's not going to fix this problem" issue, and they were going to press on with a tear down of the dif.

Thanks to the research on this site, I brought up the possibility of a TSB regarding dealer level MX on this unit...the manager looked it up and sure enough, it still stands. That said, or that read rather, he just went ahead and ordered a whole new dif unit. SHould be here Wednesday afternoon. My baby should be back to normal come the weekend...
 

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I can't speak for the 05+ but when traction control kicks in the mechanical throttle release will make a clunking noise, the pedal will feel floppy and the engine runs like 7 spark plugs were removed. It's very abrupt. I can reproduce the problem buy stomping the throttle from a stop. If you back out of the throttle a bit, it will add the timing back and take off like a ......

I get no clunks or noises from my 04 A4 drive train other than the subtle gear whine in first.

If you want to hear noises, remove the back seats......
 

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Meh, my jet is faster...
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Nope, no TC. Actually, it doesn't matter if it's on or off. Tell you guys what, since everybody is having these noise issues, yet nobody can really describe what these noises are, Im going to go take a quick ride and record the sounds. It's quite disturbing...

And for the other related posts...that knock knock knock is the ABS, like someone else mentioned. The knock comes from the rear, the 1/2 sec vibration comes from teh front. It hink it's just a system self test.

I'll be right bakc with the vid/audio.

BD0
 

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Let me smack that monkey!!
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I found this thread. This may help I have the same problem with the GTO and my Tahoe.

I have done quite a bit of work on the clunk issue since I have the problem on my CTS-V. The problem comes from the soft rubber torque coupling and the drive shaft center bearing mount. Both of these parts are made with rubber that is very soft to reduce road and gear noise inside the car. The clunk occurs when the clutch is suddenly released when there is torque on the drive shaft. The large amount of torque created on the dirve shaft in low, second, and reverse twists these rubber components like a rubber band. When you push in the clutch quickly this torque is suddenly released and the rubber parts quickly unwind. GM calls this torque reversal, but it is not actually a reversal. The clunk noise actually is not made by the drive shaft. The clunk comes from the ring and pinion gear in the differential box. When the drive shaft unwinds suddenly the pinion teeth impact the ring gear teeth and you hear the noise. The noise is loudest if you stand outside near the rear wheels. The noise is comming through the axles and into the wheels, but it is all caused by the soft rubber in the drive shaft. Some of this sudden unwinding is caused by the drive shaft itself since it appears to made from aluminum. Aluminum has one third the stiffness of steel so this causes some of the problem, but I think 90% of the problem is from the rubber. I have had emails on this subject going through the Southeastern Cadillac service rep to power train engineers at GM. Here is their response:

"The CTS-V driveline has a few "normal" operating characteristics that some customers may find objectionable. Obviously this is because the driveline was designed with high speed performance and durability as the primary criteria, pleasability issues that normally rank as high Cadillac priorities were relegated lower because this car is not like other Cadillac's. We know torque reversal in the driveline will cause an audible clunk and this can occur under various common driving/clutching conditions."

"Torque reversal is a result of normal axle backlash, the driveshaft rubber isolation flanges, the center support and the dual-mass flywheel working together. This phenomenon has been thoroughly evaluated by engineering and has been validated as not detrimental to durability or high performance usage. It is normal and no repairs should be attempted."

They will not give me the e mail address or the phone number of the engineer. Please send an e mail to: (email address removed at Robert Newman's request) and complain about this problem. Mike is the service manager for the Southeast and he will forward your comments.

You can create the clunk without moving the car. Put the parking brake on. Shift to first gear. With the engine at idle (about 1000 RPM) slowly let the clutch out until the engine bogs down to about 600 RPM. The very suddenly push in the clutch and you will hear about three clunks. Do not give the engine any gas when you are doing this. Just idle speed is good enough.

I actually blocked the car up very safely and got under the car. I trained my wife to go through this procedure while I was under the car, and I could see the drive shaft clunking back and forth.

In my younger days I was a power train engineer for off highway equipment so I know something about this issue. To me it is an unacceptable defect in the design of the CTS-V. So far Cadillac will not try to correct the problem. If you complain it will help. They tell me I am the only one complaining. The solution is to make these rubber parts from higher durometer (stiffer) rubber.
 

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Got Meth?
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when i drive it, at times, Its like loose then it Hooks up almost like its a slip then a clunk , But its not actually a slip I can tell by the engine RPM's.. i complained to my dealer they keep insisting its "normal"

Its Almost as If The Torque Converter, I dont know this, its what I think,
Like its not engaged and your in a way not exactly free wheeling, not a locked TC, then when you gas it, it slams into gear, But it doesnt make alot of sense because it seems like the noise is coming from the Differential.

Its really Hard to explain, any idea's guys? COuld it just be the clutches in the LSD acting up ?

I myself have never had an automatic that made so many noises, but i've never had a performance car either, Oh and my last car that was an Auto had a TH350 in it...

Thanks.

Diceman
My '05 A4 is going in next week for a tranny teardown with a symptom similar to yours; it occurs at low speeds (< 15mph, mostly) when applying throttle after coasting. Dropping the pan @25k miles revealed some fine metal in the filter & pan, and brownish fluid. The tranny tech at Pearson thought that debris in the valve body might be causing the windup/clunk. Since it doesn't feel like delayed band or clutch pack application to me, I'm betting on the 1/R sprag (one-way) clutch. After I see the disassembled unit, I'll post the findings.

regards, billb....
 
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