Hi all.

I'm getting a noise from my car which I at first thought might be a wheel bearing but has been since diagnosed by a Porsche Indy as a problem with the rear differential ('99 cabrio 6-speed manual).

Do you guys agree and if so, do you think I should send the entire gearboxto Gbox along with $3,500 or should I try to replace the differential myself?

The transmission has no other issues that I am aware of. it shifts great.

It seems that the differential can be replace in-suto without dropping the entire gear box. Anyone here have experience doing this?

https://drive.google.com/open?id=0B8...1phcTd5MUNhX2s

Above is a link to a recording of the sound the car makes. The sound (whomp-whomp-whomp) is independent of clutch position and varies with the speed of the car. its most noticeable when the engine is idling and the car is moving in neutral but i think this is because the engine noise just covers it up. The period of whomp-whomp sounds get longer and longer as i slow to a stop.

In the clip i am at first in neutral moving at say 10MPH until i slow to a stop. i then accelerate (engine noise) and then slow to a stop in neutral again (so you can hear the noise again).

TIA

 

maybe buy this?

https://rennlist.com/forums/parts-ma...for-996-a.html

 

Have you drained the fluid and is it silver? Then it may be the pinion bearing.

 

Is the pinion bearing part of the Differential ? I'm not sure about the color of the fluid, the indy replaced it.

 

Fluid was not silver.

 

Any updates on this?

have the same sound. You dont hear unless you turn off radio and listen for it on a quiet road. Just appeared suddenly.

 

I too am curious if this was resolved. My newly acquired 02' C4S has a similar sound

 

After the fluid was changed, the sound eventually went away.

 

Change the fluid again to take out any residual mush

 

Yes good idea, then report back in 2026 and we can put this thread to bed