996 broken bellhousing and engine vibration -Please Help-

[rmferrell]

I recently purchased a 99 911 Carrera 4. I knew it had problems and paid a low price accordingly. When I got it I found the transmission bellhousing to be cracked all the way around. I replaced the transmission and clutch. When I run the motor it vibrates severely. It always vibrates, but gets really bad above 3000 rpms. It vibrates with the clutch pushed in and shifter in neutral as well as when I am driving it. When driving I can feel a bad shudder in the clutch pedal when shifting. No check engine light and the motor seems to start up fine. It seems to have plenty of power. outside the car, you don't hear any weird noises from the engine and it doesn't clunk when I engage the clutch.

There is no body damage to the car or underside of the engine to suggest that it was in an accident. I do not know if the vibration caused the tranny to crack or something else caused the damage and vibration. There are no metal shavings in the oil. I changed the motor mounts. I have even ran the motor without the transmission installed and still got the shaking.

Is it possible that the flywheel is bad? Has anyone seen that before and replaced the dual mass flywheel and had it go away? I do not want to purchase one only to have it not be the problem.

[JFP in PA]

Do a search, there is a simple twist or defection test for the dual mass; it is a "go-no go" test, so there is no guess work.