Hi all,

I have a 2008 997.1 C2S with 54k miles, which appears to have what I can only describe as "drivetrain slack". This manifests itself as a noise whenever im in a high gear and come off the throttle then again when I reapply the throttle. It feels like the drive is dis-engaging when I throttle-off, then taking up the slack again when I reapply the throttle, making a noise in both cases.

The car is also extremely hard to get a smooth gear change in low gears (particularly in sport mode), as it seems I'm constant fighting to absolutely perfectly match the rev's for fear of feeling this jolt of slack.. It seems anything less than a perfect match results in a jolt as soon as I release the clutch. I have a lot of experience in driving all sorts of cars, from standard road cars, through to performance cars, and even race cars, but never had to work so hard to get a smooth shift.

The noise is a dull "doonk/thud" type noise. I also notice it particularly at low speed in car parks, when reversing and clutching in and then out.

I dont know if its related, but if I am shifting moderately quickly from first to second, I hear a sort of "squelch" sound from rear of the car. This doesnt affect anything, but not sure if it is all tied up in the same problem. It seems related to clutch release speed. I can recreate the same squelch noise during cruise if i keep part throttle on, and then engage / disengage the clutch. i.e. The squelch seems to happen when I slip the clutch slightly.

Occasioanlly I also hear this "squelch" when suddenly applying throttle after cruising at constant speed for a period.

Both issues are more apparent in Sport mode than standard, where the sport mode offers more sensitive throttle response.

So i am not sure whether it is Clutch / Flywheel, engine/trans bushes or something that I havent considered.

Am not even sure if there are any experts in the UK that I can take the car to, in order to be checked out?? I have full OPC warranty but they seem to dismiss most noises as "they can make a bit of noise, its wear and tear".

 

Check the engine mounts and transmission mounts. I upgraded to Function First's transmission mount inserts and it helped with "thunking" when letting up on the throttle.

 

thanks for your reponse. Are there any tell-tale signs that the engine mounts are due replacement? i.e. would it be obvious upon inspection?

did you experience any improvement in shifting smoothness too?

 

Haven't heard the various noises you hear but wife's '08 C4 does not shift as smoothly in sport mode as standard. This being our 1st Porsche, i just figured it was normal since it is so smooth in the standard mode.

 

I have same issue. had a guy look at the clutch, flywheel and slave cylinder and they all were fine. I have the car in the shop now for other issues. I may have them look at engine and transmission mounts.

 

Ok thanks for the response. Let me know if you get anywhere with the issue.

Interestingly I spoke to an Indy and he said it could be mounts but more likely sounds like flywheel, but couldn't confirm until he'd seen it.

Out of interest, how did your mechanic test and diagnose that it was not flywheel??

 

well, good question. I had a new clutch, slave cylinder and LWFW put in. ran great for a while then the problems started. the mechanic tore it down and visually inspected all three and couldn't find a problem (plus the parts were all about 1-2 months old).

 

I checked engine and tranny mounts and they were fine. must be a clutch or FW issue

 

Thanks 3POINT8,

Keep me informed of you find anything on clutch or flywheel.

Mine goes in for a geometry in 2 weeks where they will check the condition of all mounts and bushes etc. I'll report back if they find anything. Failing that I'll have clutch and flywheel inspected

 

mrush - Did you ever solve this issue? I have exactly the same issue, 2005 997 carrera, manual, 140k miles but started the slack a long time ago. Its not engine mounts or even gear box mount as had all replaced. i too am focused on the clutch and DMF but given its not slipping its a gamble to replace it all. Thanks Guy