Throw back bearings making NOISE AGAIN

zilent_jay · 10-06-2009, 06:46 PM

The noise you are hearing is the transmission... mainly gear lash.... and it's perfectly normal... all modern manual transmissions do it to some degree.... you will find this same complaint on every car forum known to man. Pretty much the only time you can hear a bad throwout bearing is when you depress the clutch pedal (disengaging the clutch and putting the throwout bearing in to use).

When your transmission is in neutral, and the clutch pedal is released (clutch engaged) the input shaft on the transmission is forced to spin with the engine. Since all of the gears in the transmission are constantly meshed, they are all turning and produce gear lash noise... along with bearings inside the transmission. When you depress the clutch and disengage the transmission from the engine, you will hear the gears inside the transmission gradually slow to a halt.... as it is no longer forced to turn with the engine.

Now... if you want to hear what a bad throwout bearing sounds like... keep the clutch pedal depressed for long periods of time every chance you get. Eventually you will wear it out.

Blown32 · 10-06-2009, 10:50 PM

Quote:

Originally Posted by zilent_jay

The noise you are hearing is the transmission... mainly gear lash.... and it's perfectly normal... all modern manual transmissions do it to some degree.... you will find this same complaint on every car forum known to man. Pretty much the only time you can hear a bad throwout bearing is when you depress the clutch pedal (disengaging the clutch and putting the throwout bearing in to use).

When your transmission is in neutral, and the clutch pedal is released (clutch engaged) the input shaft on the transmission is forced to spin with the engine. Since all of the gears in the transmission are constantly meshed, they are all turning and produce gear lash noise... along with bearings inside the transmission. When you depress the clutch and disengage the transmission from the engine, you will hear the gears inside the transmission gradually slow to a halt.... as it is no longer forced to turn with the engine.

Now... if you want to hear what a bad throwout bearing sounds like... keep the clutch pedal depressed for long periods of time every chance you get. Eventually you will wear it out.

I believe it is the throwout bearing and not the trans though!I know what you are talking about the input shaft turning.I just don't think it is that.
I"ve never heard any manual trans make that loud of a noise in neutral with the clutch pedal fully released unless a bad bearing?

Modshack · 10-07-2009, 09:40 AM

Quote:

Originally Posted by Blown32

I"ve never heard any manual trans make that loud of a noise in neutral with the clutch pedal fully released unless a bad bearing?

Quite normal, especially with a flywheel that isn't weighted correctly or damped like a dual mass set-up. It's common knowledge that installing a light(er) flywheel will result in increased gear rattle.

Blown32 · 10-07-2009, 12:14 PM

Quote:

Originally Posted by Modshack

Quite normal, especially with a flywheel that isn't weighted correctly or damped like a dual mass set-up. It's common knowledge that installing a light(er) flywheel will result in increased gear rattle.

So what your saying is a heavy flywheel dampens the gear sound?The lighter the wheel the more gear sound?

kdo2milger · 10-07-2009, 12:20 PM

my clutch throw-out bearing rattles too...i had the same issue in my BMW in Germany, it rattled like crazy, i took it to a german bmw dealership and the maint. supervisor told me it was normal...

i thought that to be odd because ive driven manuals for many many years and these are the first two cars ive ever experienced this on...

Modshack · 10-07-2009, 04:36 PM

Quote:

Originally Posted by Blown32

So what your saying is a heavy flywheel dampens the gear sound?The lighter the wheel the more gear sound?

Yes.....I've had lots f Audi buddies replace their heavy dual mass flywheels with solid billet lightweight versions only to get LOTS of gear rattle..
\
The break point on at the audi's, when putting in a new (one piece) flywheel seems to be 17lb. That or heavier and the noise is minimal, a 12lb aluminum will rattle your fillings..

Blown32 · 10-07-2009, 06:51 PM

Quote:

Originally Posted by Modshack

Yes.....I've had lots f Audi buddies replace their heavy dual mass flywheels with solid billet lightweight versions only to get LOTS of gear rattle..
\
The break point on at the audi's, when putting in a new (one piece) flywheel seems to be 17lb. That or heavier and the noise is minimal, a 12lb aluminum will rattle your fillings..

Okay thanks!Makes sense.

10-07-2009, 12:20 PM	#5 (permalink)
kdo2milger OG Priesthood Join Date: Feb 2009 Location: Fargo, ND Posts: 17,859 Drives: NISMO T Rep Power: 61	my clutch throw-out bearing rattles too...i had the same issue in my BMW in Germany, it rattled like crazy, i took it to a german bmw dealership and the maint. supervisor told me it was normal... i thought that to be odd because ive driven manuals for many many years and these are the first two cars ive ever experienced this on... __________________ Project *NISMO*

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10-06-2009, 06:46 PM	#1 (permalink)
zilent_jay Base Member Join Date: May 2009 Location: OKC Posts: 96 Drives: 2009 MB Base Sport Rep Power: 18	The noise you are hearing is the transmission... mainly gear lash.... and it's perfectly normal... all modern manual transmissions do it to some degree.... you will find this same complaint on every car forum known to man. Pretty much the only time you can hear a bad throwout bearing is when you depress the clutch pedal (disengaging the clutch and putting the throwout bearing in to use). When your transmission is in neutral, and the clutch pedal is released (clutch engaged) the input shaft on the transmission is forced to spin with the engine. Since all of the gears in the transmission are constantly meshed, they are all turning and produce gear lash noise... along with bearings inside the transmission. When you depress the clutch and disengage the transmission from the engine, you will hear the gears inside the transmission gradually slow to a halt.... as it is no longer forced to turn with the engine. Now... if you want to hear what a bad throwout bearing sounds like... keep the clutch pedal depressed for long periods of time every chance you get. Eventually you will wear it out.