[haaken675]

I am tracking down a vibration at speed. It definitely seems like my factory dual mas flywheel is bad as it makes a terrible chatter that is VERY audible when you turn the car off. If you hold teh clutch in however and shut the car down its silent.....

I was originally chasing down a wheel bearing or possibly a center support bearing. I can't find any issue so far, but now that I have realized the factory DMFW's can wear out and come apart i'm starting to lean that way...Once i get over 2,500 RPM in pretty much any gear i start feeling and hearing a vibration.....Could this be the flywheel?

[Brian86]

Originally Posted by haaken675

my factory dual mas flywheel is bad as it makes a terrible chatter that is VERY audible when you turn the car off. If you hold teh clutch in however and shut the car down its silent.....

This is basically normal behavior. I think it's more input/transfer shaft gear chatter in the gearbox as the transmission gets wear and the bearings loosen up. My new luk exhibits basically the same 'shutdown chatter' as the 280k mile one that preceded it.

Originally Posted by haaken675

Once i get over 2,500 RPM in pretty much any gear i start feeling and hearing a vibration.....Could this be the flywheel?

If the vibration is tied directly to engine RPM, and fully independent of wheel speed it points to the flywheel. Does it also vibrate in neutral, and with the clutch disengaged at the same RPMs?

This could also be the symptoms of a bad harmonic balancer on the front... although honestly I don't know much about the front pully, except that they usually last forever on these cars.

Diagnosis of the harmonic balancer is a lot easier than transmission removal. Might want to check that first.

[haaken675]

Originally Posted by Brian86

This is basically normal behavior. I think it's more input/transfer shaft gear chatter in the gearbox as the transmission gets wear and the bearings loosen up. My new luk exhibits basically the same 'shutdown chatter' as the 280k mile one that preceded it.




If the vibration is tied directly to engine RPM, and fully independent of wheel speed it points to the flywheel. Does it also vibrate in neutral, and with the clutch disengaged at the same RPMs?

This could also be the symptoms of a bad harmonic balancer on the front... although honestly I don't know much about the front pully, except that they usually last forever on these cars.

Diagnosis of the harmonic balancer is a lot easier than transmission removal. Might want to check that first.

I have revshift trans and motor mounts, so its hard to know at idle if any more vibrations are from the flywheel or not. I did try briefly today clutching in as soon as i noticed the vibration starting and it did seem to go away. Need a bit more experimenting.

Either way, i need a new clutch as its slipping under WOT with the new turbos and tune. I'm just trying to pinpoint as much as I can so i'm not just changing parts unnecessarily.