Slipping
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7th Gear
Joined: Jun 2009
Posts: 7
Likes: 0
Slipping
Over the past 3 months with 1500 miles, I have a random slipping problem (slipping - meaning it is in gear with little or no power and revs jump while attempting to accelerate). The first time this happened I thought either I was not in gear or it popped out - but that was not the case. This is with my 2004 911 turbo - 30k miles. I have driven this car around 40 times and have had 5 instances of slipping over the past 3 months. The strange thing is that I have noticed it in 2nd/3rd/4th gears. When I punch it while in 6th gear going slow - no slipping. Also, I have seen bar as high as 1.6 without slipping (in 3rd/4th gears). Out of the 5 times, 2 slipped quite bad (causing a burning smell - like the old electric race track cars when you let the wheels spin). During these 2 times, I noticed that the slipping began in 2nd and kept slipping into 3rd gear as well.
I have had bad clutches in the past, but none that behaved like this - so I need some feedback. I have talked to a couple of porsche mechanics and all say clutch. I would expect more consistency in the slipping if it were a clutch problem.
The strange thing is that when it does happen, if I pause and let the clutch engage - the slipping does not happen. It only happens when shifting gears quickly.
Any ideas - I would appreciate the feedback.
I have had bad clutches in the past, but none that behaved like this - so I need some feedback. I have talked to a couple of porsche mechanics and all say clutch. I would expect more consistency in the slipping if it were a clutch problem.
The strange thing is that when it does happen, if I pause and let the clutch engage - the slipping does not happen. It only happens when shifting gears quickly.
Any ideas - I would appreciate the feedback.
Drifting
Joined: Dec 2009
Posts: 2,919
Likes: 3
From: Aiea, HI
Match the sought gears rpm more. You can fry a clutch down shifting too especially like you clutch is now. Beware that clutch can one time be just slipping once in a while then leave you sitting there going no where the next time you turn around. Get a clutch job is my advise.
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Race Director
Joined: Oct 2005
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From: Southern Utah
Drifting
Joined: Apr 2006
Posts: 2,032
Likes: 29
From: Out West
It sounds like you have an intermittent pressure plate problem. The friction disc may be fine at this point but the pressure plate is not holding 100% all the time. You describe it like the PP may hang sometimes and by giving it time to fully "press" engagement is positive. The only thing besides a clutch issue may be a viscious coupling issue in the diff either LSD or F-R drive. I'm not familiar with working on these systems on P cars so it's just a guess. I did have some momentary slipping on a Corvette that went away with a diff oil and additive change.
Parts Specialist
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Joined: Aug 2008
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or the disc is fractured and sometimes lays flat and sometimes doesnt - the important thing to note is that we all agree its the clutch "set" just get it replaced
any chance air in the hydrolic system would cause this
any chance air in the hydrolic system would cause this
Drifting
Joined: Apr 2006
Posts: 2,032
Likes: 29
From: Out West
Air in the hydraulics may cause the clutch not to fully disengage and a spongy feel. It would have nothing to do with slipping, as the pressure plate applys engagement pressure and the disc. As the disc becomes thinner from wear it will reach a thin point where the pressure generated is not enough to hold and slipping will occur. Max pressure is with a disc of full thickness.