FIA-F1

When easing the clutch pedal out in 1st gear, car, 05 Boxster, shudders like rolling over a washboard. The higher the rpm, the less pronounced the shake. It smooths out in second gear and not detectable at speed.
Pedal travel and feel appears to be normal.

Pep!RRRR

Any oil leaking? Oil on the clutch compound might do this. Whatever the reason it doesn't sound good. Replace the IMS and RMS while you are in there.

FIA-F1

Thanks for the reply. Fortunately, this 987 has 93K miles and the bottom is bone dry, no leaks of any type. The engine was replaced by Porsche at 27K miles as part of the IMS resolution so I hope I don't have to do that again (I've heard both ways...no guarantees and Porsche fixed the problem permanently in the replacement engines). Going back to the clutch, my ignorant speculation is that some plate may be warped causing that shudder...that's what it feels like. I have heard that an option when replacing the clutch is to have a plate resurfaced. Obviously that is part of a clutch job, not a separate option. More info?

equ

- If you apply a lot of throttle at low revs in a high-ish 4th or higher gear, does the clutch hold the power or does it slip (revs go up, car doesn't accelerate)?
- During launch, if you keep the rpm's around 1500rpm by feathering gas while releasing, does it still shudder?

I don't have a 987 right now, so this is not model-specific. Just general clutch pointers...

981spyder

flywheel or plate if is not, then its oil on the clutch, but it only takes very little oil to do that.

FIA-F1

I don't want to jinx myself but there is a hint of the shudder going away. That may be a sign that it could be oil in the clutch clearing up (I don't see a bad clutch getting better). So if its oil, how are the different ways oil can get on the clutch? The bottom of the car is bone dry, not a hint of oil anywhere. There has been work done on the car recently (MAS, oil separator).

Ptech1

The pressure plates fail all the time, warp, and cause shuddering due to uneven application and release. Fluid contamination would cause slipping first, then maybe a shudder. But, even the worst RMS/IMS or transmission input shaft seal typically won't allow enough fluid onto the friction surfaces to cause this, and especially not before you noticed fluid leaks under vehicle from bellhousing area.
Replace clutch kits all the time for the same concern. Once out of vehicle and laid flat on fingers, noticeably warped.