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I have a 2010 997.2 C4S, 95K miles, 6 speed. Recently, I noticed that when I have been driving for a while (i.e. everything is heated up), when I stop at a light, then start to accelerate, about one time in 5 my transmission 'lurches', it slips. I am slowly increasing RPM's, the clutch is coming out, and it delays for a second, then 'bump', it catches. Feels like someone tapped me from behind. All the other gears seem fine. This does not do it when I first start up, when things are cold. It only starts after I've been driving a while. And as mentioned, it does not do it every time I am starting off in 1st, but it will eventually. In stop & go traffic I find myself wincing every time I start back up, waiting for the bump. What is happening here? Is this a clutch issue, or a transmission issue? And why does it only occur when things are heated up? I just had my AWD controller oil replaced, along with my front diff oil. Not sure that is related, but the issue started right after that. Thanks...
It sounds like a gearbox issue on the face of it. You could try to change the oil in the gearbox using only the OE fluid to see if it helps. If not it is possible you could need work on the gearbox. Does the gearbox currently have the original fluid in it or has it been changed in the past?
When you changed the oils for the diff and such, did you use the OE gear oil? If this literally started happening the second after you did those changes, obviously this is something to pay close attention to.
I changed the gearbox oil out about a year ago. Was having issues finding first gear after stopping. Had to hunt for it. The new oil made that transition much smoother. Gears are one thing, They have to sync up. This isn't a gear-sync issue as far as I can tell. It's happening when I begin to release the clutch and engage the transmission. That's where it's slipping. As far as I know, the shop used OE gear oil (wasn't a dealer). But the all-wheel-drive controller oil and the front differential oil I would not think would affect this. Could be wrong. It did literally start happening as I was driving away from the shop. Which is why I was suspicious of this. Not sure of the relationship between the AWD controller oil and the transmission itself slipping like that.
Never happened in my .1 MT, but Ive noticed this with my .2 MT as well. Every once in a while when letting the clutch out it seems as if the grab point changes to be a bit earlier, like I let it out to quick. Ive been driving this car for years and am very familiar with the clutch grab point. I just chalk it up to the .2s clutch auto adjust feature and forget about it.
It sounds to me like the clutch is hanging up on the splined shaft that it slides back and forth on, so although you e released the hydraulic pressure from the clutch pedal, the friction disc hasn't moved all the way back to the pressure plate. It being worse when hot totally makes sense as things swell up from heat.
I had a 928 that did exactly this. Took the clutch out, used the special stick Porsche clutch grease on the shaft and the problem has never recurred. The clutch in a 928 is the best clutch design ever and can be removed simply by taking off the lower bell housing, so 2 bolts on the starter, 6 bolts on the bell housing and you're looking at the clutch. Short splined shaft with the nose that goes into the pilot bearing releases from the torque tube via a clamp, you slide that back and the whole clutch pack drops out into your hands.
Last edited by Petza914; Sep 17, 2023 at 01:02 PM.
It sounds to me like the clutch is hanging up on the splined shaft that it slides back and forth on, so although you e released the hydraulic pressure from the clutch pedal, the friction disc hasn't moved all the way back to the pressure plate. It being worse when hot totally makes sense as things swell up from heat.
I had a 928 that did exactly this. Took the clutch out, used the special stick Porsche clutch grease on the shaft and the problem has never recurred. The clutch in a 928 is the best clutch design ever and can be removed simply by taking off the lower bell housing, so 2 bolts on the starter, 6 bolts on the bell housing and you're looking at the clutch. Short splined shaft with the nose that goes into the pilot bearing releases from the torque tube via a clamp, you slide that back and the whole clutch pack drops out into your hands.
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997.2 Transmission question
