Porsche Enthusiasts Club Forum

I have a 968 convertible with the Tiptronic gearbox. Ever since I have had it, it has had a rattle when stationary and idling that appears to come from the transmission housing. It disappears when the car is on the move or when one increases the revs when stationary. From standing outside the car it sounds as if it is an exhaust rattle, but I am pretty convinced that it is not. Any ideas please?

The manuals do this as well, I think it is a torsional vibration down the torque tube amplified by the transaxle.
I assume you mean gearbox end not engine end? If it's engine end it could be a noisy torque converter or flex plate.

Jim. Thank you. It is indeed at the gearbox end that the rattle is apparent. How does one stop the torsional vibration, or at least the noise from it?

You can't it's a fundamental part of the (Porsche) design & the four pot engine doesn't help either.
I say Porsche design because the Alfa Alfetta/75/Guiletta use the same transaxle layout but put the clutch & flywheel at the rear, just in front of the gearbox. No noise! Who said the Italians get it wrong & the Germans get it right?

Sincere thanks. At least I can stop worrying whether some bearing is going to burst throught a casting or similar disaster!

Does this description sound anything like?

"o.k., bad noise appeared, unannounced from behind the engine - thought is was a loose heat shield, maybe even a cat/exhaust problem. Or engine mount.

But, up on the lift today -worse. Ominous rattling from inside bellhousing. It's not the engine, so I'm presuming .........flywheel, ring gear, or something.........either way, it's €€€ time "


There have been a couple of owners on the 968 forum over the last few months with these symptoms and in both cases it was due to the rubber doughnut vibration damper falling apart. I think that the part itself is a fortune (>£600) and requires removal of the gear box to replace it too.

Hope this is not the problem with yours!

That is why I asked which end the noise is coming from. Tip is Auto so no flywheel but it does have a drive plate with a rubber cush drive in it. I assumed the Torque converter is in the back with the box. I've heard of the 944 drive plate breaking up & they are mega bucks, but this would be engine end, although noise echos in the tunnel so difficult to diagnose unless it's on a ramp..

The noise is definitely from the rear, and I confirmed this when the car was on a ramp. I appreciate that noise travels but I really don't think it is coming from just behind the engine. It really does sound like an exhaust rattle coming from near the rear end of the exhaust, but I know it is not! Jim's diagnosis seems to be correct.