ResB

Okay, hold your horses people. I have got it back and although I need more time in it, I'm not so sure it's been resolved. I can't tell you how fed up I am with this but I'll report back later, possibly tonight.

I couldn't get to a technician to explain to me today what the actual problem was so the young lady on the service reception tried to explain it. Not very well I hasten to add. Something to do with the Thrust bearing/plate...mind you if it hasn't been resolved, it's irrelevant.

MichaelL

I have had the "thump", occasionally, at cold car temperatures on startup, since new. Now have 27K + miles. Can't say that it is a problem.

ResB

Mine's not just when its cold. I think that's because you have had it from new. For me, it just started happening after 20,000 miles of trouble free motoring, therefore there is a defining moment when this issue appeared. It doesn't feel normal to me. Perhaps I'm more particular about this sort of thing than you are.

ResB

Just out of interest guys, do those with the "clutch thump" have the short shift fitted?

ECS

Res, I have the regular shifter and it does the same thing.

Fahrer

Do you all have a "S" ( those experiencing the thump)? I believe the S has a somewhat different setup?

ECS

Mine is a "S". My '02 996C2 did not have this problem. I believe the regular 997 is very similar to the 996 set-up. My original thought was maybe it had something to do with this clutch being self adjusting.

Porky

ResB - what happens if the sticking thrust bearing is not fixed?

ECS

Guys,

I got in contact with the PCA tech committee person who is in charge of technical questions for the 997 in Panorama. Here is his answer to the question regarding the clutch thumping. Quite interesting. This group is usually pretty good.
===============================================
ANS FROM TECH COMMITTEE:
It is actually internally in the gearbox. We have seen this before, somehow the Japanese gearbox seems to keep a gear engaged partially and when you let out the clutch, the noise is the gear releasing the mainshaft. We cannot fix these things and can only replace so we really don't know what exactly it is.

Right now we replace the whole thing since we cannot get any spare parts to fix them yet. I don't think it's a big issue, more of an annoyance.

PCA Tech Committee, 997 and Cayenne
==============================================================

sunlion

I too have had this from day 1. It happens when I engage or disengage the clutch and is a very subtle noise. I was able to demonstrate it to the service rep at my dealership in Seattle. He said it had to do with the hydraulic assit for the clutch, just a built up of pressure. It has never affected the performance of my car so I accepted this explanation as it sounded reasonable. '05, non-S, stock.

ECS

Sunlion, I don't believe the thump we are talking about is when the clutch is engaged. Only when it is released in neutral.

ianwallwork

I think this 'thump' is perfectly normal. It is caused when the clutch is released in neutral and the internals of the gearbox were stationary. Releasing the clutch accelerates all the gearbox internals (quite a lot of weight in there) to crank speed very suddenly causing the thump. And it IS repeatable.

Try this: run the engine at idle with the car in neutral and the handbrake on. If you depress the clutch and release, you will not get a thump as the gearbox internals are already turning. Now depress the clutch and put the gearbox in first. Keeping the clutch depressed, go back to neutral. Now release the clutch and you will get the thump - putting the 'box in gear stopped the gearbox internals and releasing the clutch in this case spun them up again with a thump!

Perfectly normal and nothing to worry about.

Ian W

rotthaus

Mine has thumped while cold since new. It also like to be double-clutched to get back into first when cold. Having the transmission up to temp appears to alleviate both issues.

ResB

It can't be normal as this just suddenly started happening on mine, it was like night and day the difference. It also happens to me (not sure if it's related) if you change gear as you would do if you were driving spiritedly the thump also happens for me just as you release the clutch to the full extent and is more noticeable from 1st to 2nd and then 3rd.

Anyway, it's back with the OPC for the 4th time. They recognise there is an issue and have called me to say that they have finally resolved it. I'll know more on Monday but fingers crossed.

So, it isn't the dual mass flywheel, the sticking thrust bearing, or resolved by bleading the clutch but this time they say they've done it... We'll see on Monday....

I'll keep you updated...

ResB

Arrived at the OPC just after lunch today to be greeted by two service girls grinning like cheshire cats and a large welcoming "Hi", nice to see you again! I smiled politely and said ",so, is she done?" Yes they exclaim.

OPC - "Can you just wait a moment as we want one of the technicians to go out on a test drive with you?"

Me - "Yeah, of course". This could be a winner I'm thinking as I've been told they are 110% sure they have resolved the issue and cannot recreate the "dreaded thump".

So, work done to the car to resolve the problem.

1. New Dual Mass Flywheel.
2. Clutch bled.
3. Sticking thrust bearing
4. New Clutch (this time)

So, the technician arrives, gives me my key with another great big smile on his face and we make our way to the car just outside.

We both sit in it, I start the car. Clutch feels good, which it should do as it's new. Into reverse with handbrake on, take up the biting point, dip the clutch, take it out of gear and let the clutch out.......

"THUMP!!"...

Look to the passenger side and the technician has his head in his hands....

Good fix fella's. I'm a happy chappy once again. That's 4 attempts and 4 failures. I wouldn't mind but its almost a 200 mile round trip to the dealers.

They think about it for a while, speak with Porsche GB, and suggest it might be movement in the rear struts. Okay I say. Change the bushes or whatever and I'll wait.

1 hour later the problem is still there.

Final straw. They have ordered a new gearbox which should take about a week to come, so one more visit should finally see an end to it. Having said this I did say it was a gearbox issue from the beginning.

So, it still isn't resolved but there may be some light at the end of the tunnel. We'll see in the next exciting episode of "my tranny dun't work propper".