Clutch/PDK gearbox crunching noise?

[kevinli4877]

Is anyone else having similar issues?
I brought my first ever Porsche (approved used) from a Porsche dealership just before Christmas and went for the 991 C2S cabriolet (2012 registration) with a PDK gearbox. When I first drive the car (typically first thing in the morning when it's cold) and it shifts gears, normally down from say 2nd to 1st, I hear this very loud crunching noise from I guess the clutch/gearbox.....basically it sounds like a bad gear change. This happens for the first 30-60 secs of driving but then disappears....I guess once the clutch/gearbox has warmed up or has been used.
The car is still under warranty so I took it into Porsche Reading (my nearest dealership) for investigation. The Porsche engineer heard the crunching noise once and did confirm this wasn't normal but wasn't able to reproduce the noise again later on that day. Porsche Reading said they couldn't look into the issue any further until they had evidence of the issue ie. apparently they need a recording of the noise. But in typical fashion since I've had the car back I can't reproduce the noise either but then again the outside temperature has increased quite a bit since Dec/Jan (when it happened most frequently) ie. from below 2 degrees in the morning to about 6+ degrees most mornings now.

Do you think I should be worried?
And do you think I should push for Porsche Reading to investigate this even though I have no recording or evidence as they say, even though one of Porsche's own engineers did hear the noise and confirmed that this wasn't normal?

Would love to hear people's thoughts.

 

[PJ63]

I had a 2012 991 C2 which I've only just sold but never had any noise or issue in the 2 years I had it. It's been the best 911 I've had with absolutely no problems so I wouldn't say what yours is doing is normal. If it was me I'd get them to have it overnight so they could drive it first thing whilst it's cold. Hope you get it sorted.

 

[salisbees]

At the risk of being trite, are you sure that this is not the noise made by the tyres when cold? It is a loud graunching which occurs on steering lock, in cold weather. To leave my house I have to make a slow speed right turn on hard standing. When I first had mine, in a cold November, I too was concerned by such a noise which disappeared after movement. I am on summer tyres and the noise returns every time the temperature drops below five degrees and is not noticeable unless you use the car all year. I had this checked out and confirmed by my OPC. Hope this helps!

 

[kevinli4877]

Hi Howard,
Thanks for replying. I don't believe it's the tyres as the noise is very 'mechanical' in nature plus it has happened several times when I'm driving in a straight line approaching a junction for example, allowing the gears to drop to 1st. Also the Porsche engineer confirmed he heard the noise and thought it was from the gearbox/clutch. I guess I just need my iPhone on record at the start of every journey....just hope there aren't any police watching me at the time!

 

[Lancerlot]

Yes, I think you should be concerned and yes you should push for it to be further investigated.
I'm curious as to why you're referring it to different Centres when you should really concentrate on the original supplying Centre as it should have a special interest in putting things right. Have you checked with the previous owner to see if he had the problem and if so, was the Centre aware of it?
Also, I can't imagine a scenario where you are changing down from 2nd to 1st gear within the first 30-60 seconds of your journey. Are you changing manually or it this auto change?
It's customary for there to be a slight delay from cold as drive is taken up, but this is normal, silent and disappears as soon as the transmission fluid warms.
An interesting topic. Please keep us updated.
Regards,
Clive.

 

[lowndes]

I have had PDK in various 997 and 991 and never experienced the sort of noises you describe. I would say it was quite unusual and not typical.
On the plus side the Porsche engineer has also heard the noise, though was subsequently unable to replicate it; it is frustrating when faults are intermittent.[] I would make sure I have a written record, dates and times who said what etc of exactly what transpired when the Porsche engineer tested the car.
My understanding is that the nature of PDK is such that it is almost impossible for the user to damage it by missed gear changes etc. which suggests the fault may lie in the manufacture rather than as a result of previous misuse.

 

[kevinli4877]

Hi Clive, Nicholas
Thanks for the replies, it's greatly appreciated...I will chase this up with Porsche and fortunately have had written confirmation of everything in email.
Below are my the responses to your queries:

• Different Centres - I brought my car from Porsche Mayfair but Porsche Reading is by far my nearest Centre so just been using them as it's under warranty still. However, if I don't get a decent response from them I'll go back to Porsche Mayfair but will ask them if they've had any issues like this before....although when I brought it I did ask were there any known problems to which they said no.
• Changing gears within 30-60 secs - I live in a cul-de-sac and the stretch of road is only 50m before I reach a junction so the car gets into 2nd gear then shifts down to 1st when I stop at the junction. I really only use the auto change.

Will let you know how I get on and more importantly Porsche's response, especially as their own engineer heard the issue and confirmed it's not normal.

Thanks to all.

Kevin

 

[fireblade]

Not had any problems with my 2014 991 Turbo S PDK on road or track. They are supposed to be unbreakable so if it continues you should persist as it is not normal.

I know that it is not the same but no problems either with my Tiptronic 997 Turbo.

Had a whining noise from my Tiptronic 996C4S which seemed to come from the transmission tunnel but engineer correctly diagnosed it as a fan bearing. The engineer stated that these gearboxes / clutches are an immense improvement over previous Porsche ones as I found out to my cost as I managed to destroy my 964C4S clutch just after expiry of warranty when I have never had a clutch problem ever before.

Good luck

 

[Lancerlot]

Assuming it's not something simple like brake noise on initial application first thing in the morning, I would certainly get the potential defect added to the vehicle record. Then, if you can't get to the bottom of it atm, enjoy the car and see if it develops within the remaining warranty period.
I bought my last 2 cars from Mayfair. They're part of Porsche Retail along with Reading, Hatfield and others. I would go back to theguy who sold it to you and/or speak to the Dealer Principal and tell them you're unhappy. If you deal with Reading speak to Tim on the service desk there. He's a good guy and will do his best to help.
As a new owner, you need to be 100% happy & confident with your purchase.
Good luck.
Clive.