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      05-02-2012, 10:20 PM   #23
RPM90
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Quote:
Originally Posted by flzrider View Post
I don't see how that would ever be the case when there is no load on the T.O. bearing when your foot is off the pedal. The bearing is not even spinning.
Your thinking is sound.
However, I've had a bad/worn TOB and the symptoms were the same, when in neutral and clutch pedal not depressed there was a rattling sound.
When I pushed the clutch pedal in the noise would stop.

I think the key here is when in "neutral", and the clutch is engaged, meaning the pedal is not being pushed in.
Pushing the pedal in activates the TOB to push against pressure plate release to move the clutch away from the flywheel. At that point the TOB is under pressure and no noise.

Sitting in neutral, clutch pedal up, there is no pressure on the TOB, as the clutch is engaged and if it's a good bearing then no noise. But, if it's worn it can still rattle as the input shaft is still spinning.

Doing reading on this you find many have said that they hear a rattle when they push the pedal in. And, then there are others who say they hear the rattle when the pedal is not pushed in.
As you or the other poster said, IF everything is fine, then there SHOULD be no noise. But a bad/worn TOB isn't fine, there's something wrong with it.
That could explain why we hear/read of rattling when the pedal is depressed and when it's released.

I'll repeat this again, also for my own thinking to try and keep this straight.
I think the difference is if the trans is in neutral or in gear.
When in gear, and the pedal is depressed, the clutch separates from the flywheel. Once the trans input slows and stops there should be no noise as long as the clutch pedal is pushed in.
Once it's released the clutch contacts the flywheel and we're moving.
Perhaps we're just not hearing an loss TOB tolerance due to all the other sounds coming from the engine, trans, and car in motion.

When the car comes to a stop, the clutch pedal is pushed and the clutch disengages, trans rotations stop and no noise, as long as the pedal stays pushed in.

But, if neutral is selected, and the clutch pedal is released, the clutch is engaged to the flywheel and the trans input shaft is spinning, and if the TOB is loose, or not greased properly, it could still make a rattle sound.
Push the clutch pedal in and it puts pressure on the TOB and rattling stops.

What do you think?
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      05-02-2012, 11:38 PM   #24
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Agreed it's not that bearing, due to the whole makes-noise-when-TOB-is-not-spinning thing.

Clutch hub rattling in the disc or the disc on the input shaft?

My last car had the noise, and a new clutch install fixed it. Did it at the dealer, the service manager did the work himself and while I was on the floor chatting w/ him he gave me the long version of why it wasn't the TOB. I can't see this car being any different in the function of the TOB being backwards from the other manual trannies in the world.
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      05-03-2012, 07:20 PM   #25
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it was making noise while in neutral and the clutch pedal not pressed in...

i brought it to the dealer, and they confirmed that it was the throw out bearing making noise and replaced it today, and said the noise was gone
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      05-03-2012, 08:11 PM   #26
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Quote:
Originally Posted by tracer bullet View Post
Agreed it's not that bearing, due to the whole makes-noise-when-TOB-is-not-spinning thing.

Clutch hub rattling in the disc or the disc on the input shaft?

My last car had the noise, and a new clutch install fixed it. Did it at the dealer, the service manager did the work himself and while I was on the floor chatting w/ him he gave me the long version of why it wasn't the TOB. I can't see this car being any different in the function of the TOB being backwards from the other manual trannies in the world.
Actually, it was the TOB.

The OP has already confirmed that.
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      05-03-2012, 10:36 PM   #27
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If it's confirmed it was confirmed in his post after mine, after the work was done, not before. Not sure what your point is.

Still doesn't make sense, TOB spins with the clutch pedal in, not out. I don't normally see things making noise when they sit still, only things nearby that are moving. Makes me wonder what if anything else was replaced, adjusted, or tightened during the procedure. Unless we were there during the install we'll never know for sure.

Whatever, doesn't matter, fixed is fixed. That's always a good thing. Noises like this (whatever they are from), even when called "cosmetic" are annoying as hell! Congrats on that at least, and getting it done under warranty.
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      05-04-2012, 09:59 PM   #28
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Quote:
Originally Posted by tracer bullet View Post
If it's confirmed it was confirmed in his post after mine, after the work was done, not before. Not sure what your point is.

Still doesn't make sense, TOB spins with the clutch pedal in, not out. I don't normally see things making noise when they sit still, only things nearby that are moving. Makes me wonder what if anything else was replaced, adjusted, or tightened during the procedure. Unless we were there during the install we'll never know for sure.

Whatever, doesn't matter, fixed is fixed. That's always a good thing. Noises like this (whatever they are from), even when called "cosmetic" are annoying as hell! Congrats on that at least, and getting it done under warranty.
What do you mean, what do I mean? Just kidding.
I was just pointing out that even though there is question about the noise being from the TOB, in this case it is the TOB.

So, I mean nothing bad with my comment.

As far as can the TOB make noise when the clutch pedal is not pressed in, I wrote a post addressing that very question.

To recap it, I too had a car with a bad/worn TOB, and it too made noise when the pedal was out, and the noise stopped when the pedal was pushed in. In my post about that, above, I offered an explanation of how that can be.
I know it's odd, as many say a bad TOB should only make noise when the clutch is disengaged, pedal in.
Yet, some say that it happens when the clutch is engaged, pedal out.
So with the noise being there when the pedal is out, it may be something else, like a input shaft bearing.
But, in many cases the noise with the pedal out has been the TOB, and some times all it takes is simply to grease it.
Please read my discussion post above and feel free to comment.

Last edited by RPM90; 05-05-2012 at 12:18 AM.
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      05-05-2012, 12:17 AM   #29
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Ok, I've some more extensive reading and have some diagnostic to add to this that may help others in the future.

So, engine running, trans in neutral.
There is a noise.
Question; is it the throw out bearing or the input shaft bearing?

Things to do to diagnose:
If you LIGHTLY press the clutch pedal and the noise stops, it's likely the TOB.
Why? In neutral, clutch pedal out, the clutch is engaged. The input shaft to the trans is spinning. The TOB sits around the input shaft. If the TOB is out of spec, or not lubed properly, it could rattle around the input shaft.
By pressing lightly on the clutch pedal, pedal NOT pushed in, there is load on the TOB and stabilizes it enough to stop the rattling.

If a light push on the clutch pedal does not stop the noise, then push the clutch pedal all the way in. This will fully disengage the clutch from the flywheel and the input shaft will soon stop spinning. If the noise then stops, it could likely be the input shaft bearing.

The input shaft bearing is a precision piece and has ball bearings in it's construction. The ball bearings could fail or gain greater tolerance between them. As the input shaft spins, it spins those bearings and you'll hear it making noise. Also, the bearing itself can be worn thus creating a larger tolerance that could allow the bearing to rattle around the shaft. The noise created by the input shaft bearing may make a more whirring type sounds. That noise/sound will change with engine speed/rpm. As the engine speed changes so to will the sound/noise of the bad input shaft bearing.

I hope this can help someone in the future with trying to diagnose this noisy problem. The research helped me to understand this issue better.
It also explains why there seem to be 2 different viewpoints on the issue.
If there is a noise and you lightly push on the clutch pedal and the sound stops, then it's likely the TOB. If you have to fully depress the clutch pedal for the sound to stop, then it's likely the input shaft bearing.
Of course this info is for diagnostic and until you actually get in the trans to find the exact problem, you can't be 100% positive. Hopefully this will get you to around 80%.
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      05-06-2012, 06:36 PM   #30
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Quote:
Originally Posted by RPM90 View Post
Ok, I've some more extensive reading and have some diagnostic to add to this that may help others in the future.

So, engine running, trans in neutral.
There is a noise.
Question; is it the throw out bearing or the input shaft bearing?

Things to do to diagnose:
If you LIGHTLY press the clutch pedal and the noise stops, it's likely the TOB.
Why? In neutral, clutch pedal out, the clutch is engaged. The input shaft to the trans is spinning. The TOB sits around the input shaft. If the TOB is out of spec, or not lubed properly, it could rattle around the input shaft.
By pressing lightly on the clutch pedal, pedal NOT pushed in, there is load on the TOB and stabilizes it enough to stop the rattling.


If a light push on the clutch pedal does not stop the noise, then push the clutch pedal all the way in. This will fully disengage the clutch from the flywheel and the input shaft will soon stop spinning. If the noise then stops, it could likely be the input shaft bearing.

The input shaft bearing is a precision piece and has ball bearings in it's construction. The ball bearings could fail or gain greater tolerance between them. As the input shaft spins, it spins those bearings and you'll hear it making noise. Also, the bearing itself can be worn thus creating a larger tolerance that could allow the bearing to rattle around the shaft. The noise created by the input shaft bearing may make a more whirring type sounds. That noise/sound will change with engine speed/rpm. As the engine speed changes so to will the sound/noise of the bad input shaft bearing.

I hope this can help someone in the future with trying to diagnose this noisy problem. The research helped me to understand this issue better.
It also explains why there seem to be 2 different viewpoints on the issue.
If there is a noise and you lightly push on the clutch pedal and the sound stops, then it's likely the TOB. If you have to fully depress the clutch pedal for the sound to stop, then it's likely the input shaft bearing.
Of course this info is for diagnostic and until you actually get in the trans to find the exact problem, you can't be 100% positive. Hopefully this will get you to around 80%.

awesome post pal!


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      05-06-2012, 09:38 PM   #31
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It's a good thought process on it, makes sense. Would be kinda fun to have someone's car opened up to poke around on. Doubt we'd find any takers
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      05-07-2012, 11:30 PM   #32
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I hope it helps someone in the future.
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