throw out bearing issues

[JB5]

Hi Guys,

just want to see your inputs on this issue I'm having. I recently finished swapping a 2.7t to my 02 6spd B6 which uses the same transmission as the B5 S4.
I installed a JHM aluminum flywheel with the RS4 PP, which I really like the feel and everything about it. Here's the issue I'm having.

When I turn the car on (cold), I hear a rattle slightly loud. Initially I thought a lifter was bad, but after much inspection the sound appeared to come from the back of the motor.
When I press the clutch pedal and released the sound went away. At this point, it was a very low noise rattle. When driving while the car is cold, I hear the slight rattle when I press the clutch pedal but goes away when I release. After driving for a while (many shifts), car warmed up and all, sound disappears. it's like the Throw out bearing fixed itself when warmed up.

one thing to note: when I did the swap, I turned the car on several times during the engine testing before I put it all together, (there was no rattle of any kind). I found a huge water leak on the main seal and i had to put the tranny down to fix that. I then put the tranny back up, but did not remove or bled the slave cylinder and used the tranny bolts to mate the tranny and engine for the last 1/2 inch. is there a possibility that my new throw-out bearing got damaged with this? I fear that this is the case but just wanted your opinion. I'm sure I can do this in a weekend, I've put the tranny down so many times.

If the throw-out bearing is bad, based on my symptoms,
- how long do you give it till it blows?
- if this were to happen on the road, will it still be driveable so I can get the car home?

your help/opinion is much appreciate it.

here's a picture of the engine on the B6 in case you like seeing pictures ;)

[S4gasm aka LOTR]

aluminum FW's will quite often have chatter. Are you sure you're not just experiencing FW chatter?

[Monty23]

The rattle is from the aluminum flywheel. It's very common and very annoying. My fidanza flywheel did it as well. I'm pretty sure the rattle actually comes from the alignment dowel pins for the pressure plate. They are steel and just pressed into the aluminum. Since aluminum expands much more than steel at elevated temp, the holes get bigger than the dowels. My dowels were all loose when i removed my flywheel to replace it with the steel ttv replacement i bought.

[vavJETTAw36]

Same chattery sound on my S4 running Fidanza LWFW. If i ever have issues with clutch or tranny, the FW is getting pulled out so quick! I hate it.

[JB5]

I understand, how you may think it's flywheel chatter. I'm familiar with that sound. However, the sound is only present at cold starts. Once the car warms up, there's no more sound. Besides, wouldn't the chatter be present through RPM range while driving? When car is cold, the sound is there when I press the clutch pedal.

[Monty23]

Mine only made noise at idle in neutral with the clutch out.

[bajanavant]

I had the same issue with both of my south bend tob but it goes away after a while about 300 miles never any engagement issues just annoying but it should go away

[JB5]

Thanks all for your awesome responses. Will just drive like it is now. Looks like it may not be a real urgent problem then.

[JB5]

One last thing to just finalize this analysis. I took two videos one when you can hear the chatter (cold start) and one when the chatter is not there (warmed up).

Chatter present:


Chatter not present:


one important thing to note is that even though the chatter is present , there is absolutely no vibrations felt on the pedal.
the way I can explain it is like, if you have a noise on your brakes related to bad rotors sometimes you can feel the brake pedal vibrate, so I would think that if the TOB was out I should feel the clutch pedal vibrate when engaging. is this analogy wrong? possibly this "issue" is not really an issue and is just flywheel chatter?

thanks again guys,


**Edit**
finally learned how to post videos, sorry for the cell quality