Not that I'm a big downshifter, I usually rev match my shiftingbut when there is drag from downshifting the rear-end shudders (vibrates)slightly. In the old days we used to tag that similar feeling as a bad u-joint. I recently had a Porsche tech give me his diag and he felt that even though the clutch wasa fairly recent replacement (spring, not rubber) that he would go for a new clutch.Is there anythingelse it might be that causing this... only because this shudder feelsmorelikea rearend "hopping" than clutch vibration or slip. (The clutch hooks upperfectly when "accelerating" through the gears. It only does this when downshifting in any gear.)I have access to a hoist and a general techif Iknew what to look for.

 

My guess is your clutch is fine if it has a spring center, and that you just need to rev match better. The rear end is going to shudder if you don't on a down shift. You can also check your upper tranny mounts to make sure they are nice and tight, and make sure there is no play in your CV joints.

 

I'll take that good advice and work on my shifting technique. I guess I'm an old dog that has to learn how to rev match all shifting. 25 years ago we used to be able to slam those old240Zs into corners sideways and come out as straight as an arrow by downshifting to kick the rear endinto a drift. Guess you don't do that with a Porsche... I've gotnewCVs, axles n' boots so I'll be looking at those mounts real soon. Thanks again Doc.

 

I have such as nasty clutch in my 951, that if you don't rev match perfectly on a downshift on the street, you will chatter your teeth out. On the track if you miss it, and are braking hard, you don't have to worry about turning, because you will already be sideways going into the corner, lol.

 

There ya go! That's the way I used to steer when I was still brave enough!!