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Discussion Starter · #1 · (Edited)
After replacing my front motor mount and left-hand rear motor mount (tranny mount) I took my '98 2.0 GTI for a test drive when halfway through I heard a pop. Now whenever I'm coasting or off the gas at all there's an audible clicking. It does not matter whether I'm in neutral or in gear, clutch in or out, while the car is moving there is a clicking that is in sync with the speed of the car. However the noise completely goes away whenever there is any load on the drive-train no matter how small but returns as soon as you left off and coast. I have 3 vids here of the car up on stands while in 3rd gear accelerating and decelerating RPMs. Any advice or opinions would be appreciated, as of now I'm assuming the noise is my differential or I need a tranny rebuild. Thanks


 

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as of now I'm assuming the noise is my differential or I need a tranny rebuild.
I'm with HGB on this one... I bet the small taper bearing on the bottom of the output shaft is shot.
Pull it apart to fix it... driving it can lead to total failure of the bearing, and if a roller gets loose and gets between the R&P it'll kill all sorts of expensive parts in there, so stop driving it now.;)

The helical design of the teeth cause thrust forces axially along the shafts... the gears want to slide up and down away from each other, basically.

The R&P gears are helical... the thrust forces will shove the output shaft towards 5th gear under acceleration, increasing the load on the large taper bearing that secures the shaft. These forces reverse any time the engine is being driven by the trans. When in gear and off the throttle, the momentum of the car will cause the engine to rev, just like downshifting and letting the clutch out revs the engine up. This is when the thrust forces reverse in the trans so when not accelerating, the output shaft is shoved away from the large bearing and into the small bearing.

As soon as you let off the throttle in your vids, the thrust forces reverse and load the small bearing on the output shaft. As soon as you apply throttle to make the engine drive the trans and not the other way around, the forces go back to normal and that small bearing is unloaded and the forces shove the shaft into the big bearing, which is better sized to cope with the load.

That small bearing is almost always worn in the trans I open here. That bearing is why I started having all the bearings I keep in stock cryo treated. I had read that some taper bearings have experienced 300% increase in service life due to the increased wear resistance that cryo offers, so I started having the bearings treated, just as an attempt to negate the accelerated wear of that small tapered bearing.
 

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Discussion Starter · #4 ·
Thanks for the input so far, both of what you guys said make a lot of sense. Trans is out of the car now and I'll be taking it to NGP for them to take a look, I'll let you guys know what they tell me as soon as I find out. Your input may benefit them as well so thanks again.
 

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Omg I'm gonna cry. :( I know this thread is like over a year old but my car is doing the same. I was wondering though since there weren't any additional replies if anyone else has had this issue and had it fixed and how much it cost? I'm smart and a patient but I don't think I have the skills and definitely don't have to tools or garage to do any internal repairs to the engine or tranny. Thanks
 

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I know this thread is like over a year old but my car is doing the same. I was wondering though since there weren't any additional replies if anyone else has had this issue and had it fixed and how much it cost?
It will cost ALL your money, then $50 more. The thread is 5 days old. It is still 2011.;)

It's basically a rebuild... some places cost more than others, it depends on the price of the parts you put in, how many parts you end up putting in, and the labor rate.... $600-$700 on the low end, $1000+ on the high end. Anything over that is a bit much unless there is other damaged parts in there.:thumbup:
 

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Oops on me for thinking the thread was over a year old. It was panic moment because its something i cannot fix myself. Lol!! Thanks for the info and thank you to the person that posted the thread in the first place. I had no idea how to describe what went wrong.
 

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Discussion Starter · #8 ·
Haha yea no problem, I'll let you know what it is and how much it costs when they're done. Dropped it off last Weds. or so and called Sat. and they haven't looked at it yet ha. So if you haven't taken yours anywhere by the time I hear back from them, check on here in a week or so
 

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Any updates?

I have the same issue and any insight you can provide would be great.

Haha yea no problem, I'll let you know what it is and how much it costs when they're done. Dropped it off last Weds. or so and called Sat. and they haven't looked at it yet ha. So if you haven't taken yours anywhere by the time I hear back from them, check on here in a week or so
 

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Discussion Starter · #10 ·
Sorry, it's taken so long I figured no one was following anymore. The noise was coming from a damaged ring and pinion inside the differential. They told me they were waiting on a parts tranny to reduce the costs which is why it took so long, turned out the parts tranny was damaged as well. He said it would be about 1080.00 in new parts without labor included so I told them not to worry about it and I'm in the progress of installing a used tranny I found on here. Sorry again and good luck
 

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Just had this happen to me on the way home. Freakin awesome, now I have no car to drive. I'm working on my BMW diff, then my VW diff screws up. Sounds like the stupid rivets gave on the ring gear of the diff. Pretty common. They make bolt kits for it, I just don't wanna drop the transmission because I did it only 1000 miles ago.
 

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i hope its simple

Ive got a 98 saab 9000. when i bought it a couple months ago, the transmission was making a ratteling sound at idle. I increased the idle speed and the noise went away. I started having noises in 2nd and 3rd gear that started off loud but then in a few days the noise stopped. the last thing to happen was the gears were hard to shift and started making a funny noise when at start off. Yesterday i added trans oil and drove it severval miles and it helped alot. There were no sounds. Now today I was pulling out of the drive, the car started jumping, i heard a pop and now it is making the cliking sound while coasting. all the gears feel smooth as glass and there are no sounds while under torqe. Would changing the oil help or does it just need to be repaired. All the other sounds and problems seemed to work them selves out over time.

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thanks for all the info. atleast now im prepared to pull the trans I just hope it might be something simple.
 

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Now the tread is more than a year old...

Exactly the info I needed the vids were a huge help in finding out what that sound is. Guess ill keep running the trans until something fails than source a used one. Been making that noise for about 10k, nearly 30k whining in neutral(not TO bearing) and reverse has clattered bad since I got it. Too bad though, it shifts really smooth. Smoothest shifting 020 I've had yet.
 

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Discussion Starter · #15 ·
I'm glad the thread could help some, just an update years later for anyone else who comes across this...while I had the old used tranny in I had changed my mind and got the original one fixed. I don't remember the circumstances but the price was reduced some and when all was said and done it was $795. Been running it since and all is good.
 
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