Just wanted to post an update.
Replaced the flex disk/Guibo but did not make any difference unfortunately. Disconnected the driveshaft and problem still occurred.
I remember in my z06 you had to run a friction modifier/additive in the differentials, but I don't recall Porsches' needing that. Am I correct on that?
Only other things I can think of would be a completely shot motor mount but that seems unlikely.
Any advice welcomed before it goes to a shop for diagnosing.

 

Mine seems to do it more after driving it hard or after driving it longer than 15 miles. Haven’t had time to diagnose and really only drive it 5 miles at a time. I’m leaning towards motor mounts.

 

Thanks for the update.
You shouldn't need any sort of friction modifier. OEM Porsche gear oil should be the ticket.

The only other thing I could think of would be to bleed the hydraulic system and look for any leaks. I kinda wonder if there is some sort of pressure build up in the system that is/isnt being released as it should thats causing something to bind then release. IDK, grasping at straws here. There are only so many external components to look at and replace before you'd need to dig into the transmission...

Slightly off topic but you might consider asking this question on rennlist>997 turbo forum. 6speed is fine, but rennlist is much more active these days. Maybe someone knowledgeable there has an idea.

 

OK, at least you can rule out the front drive train.

Anyway you can get a recording of the sound?

Is it only acceleration forward? Can you get it to do it while turning? Turning without acceleration? How about reverse (I know much more challenging to test)? Going over bumps at any speed?

And this does NOT happen above 1st gear? Even if you hit it hard in 2nd?

I am pretty sure you didn't mess with the mounts when doing the fluid work, but have you checked the torque on both engine and transmission mounts? Also give the rear suspension a look when you are checking to see if there are any distorted bushings (though I would think you would sense an issue in all gears).

Do you feel it in the steering wheel when it happens?

Ed

 

Seems we have the same issue. Hopefully one of us will get it figured out.

 

Change in clutch after warming up - as mentioned check Hydraulics, slave and master or accumulator

Occasionally my clutch will feel stiff after being parked for a couple of days, then normal after starting . . .

https://www.renntech.org/tutorials/a...r-replacement/

Good luck!

 

Been following this thread a bit.

I have a similar sound coming from the transmission/rear end. I'd describe it more as a 'clunk'. It happens sporadically at about 5 mph as I come to a stop. Doesn't matter if I'm in neutral or in a gear with the clutch in. There is an audible clunk and I can feel it through the seat. This happens ~1/10 times I come to a stop. Haven't been able to get it repeatable... Just decides to clunk when it wants...

About the car: 07, 6sp, locking diff, ~50k miles. No issues shifting, this is purely an annoyance.

So far I've tried semi solid engine mounts. That made it much more noticeable. Took them off and replaced with new OEM. Clunk still there. Thought about doing transmission mounts but based on the engine mount replacement, I don't think its something loose down there.

Next up will be a system bleed and new slave cylinder. The inconsistency of the clunk makes me think it could be pressure related.