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Clutch slipping but not sure why

jepherz

Staff member
Joined
Aug 8, 2004
Messages
7,877
Location
KC, Missouri
I have an RPS 2900 lb pressure plate mated to a 6 puck clutch plate with copper and organic discs mated to a stock flywheel. The clutch has less than 3000 miles on it and has never been beat on. A majority of that time was spent at track days (road course) but no launching or anything took place. I pulled the trans thinking one of the seals went and the disc was slipping on oil, but I've now found it to be dry. There is also no signs of blue from heat at all. I'd hate to have to throw the clutch away when it appears there is just some spec that is off either on the pressure plate or the flywheel.

Anybody have any suggestions for me? Maybe I just need to call RPS and find out their clearances for everything and bust out the measuring tools?
 

start simple and make sure the slave cylinder is letting the clutch engauge fully. easiest way is just taking it off and see if the throw out arm moves back, or by making sure there is free play in the clutch pedal before you get any pressure feeling. after that it sounds like a step depth issue on your stock flywheel
 

grocery_getter

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Joined
Jun 20, 2004
Messages
1,225
Location
Kent - industrial suburbs of Seattle, WA
Well, what is required flywheel step on the RPS clutch? What is yours at?

If the clutch is actually slipping, then you should see signs of metal slipping on the flywheel or the pressure plate. If you don't see any sign of slipping at all then maybe its not the clutch, maybe its engine problem? Do you smell clutch at all when it felt like it was slipping in the past? How did you determined that the clutch was slipping? Rpm goes around the gauge faster than the car is gaining speed compared to before?
 

its pretty hard to tell normal clutch slippage compared to moderat slippage, especially in an awd car because as im sure you know the friction disk slips between the pressure plate and flywheel during every engaugement
 

jepherz

Staff member
Joined
Aug 8, 2004
Messages
7,877
Location
KC, Missouri
Thanks for the replies. Mucho helpful.

Stupid me didn't think to check the clutch disengagement per the pedal before I pulled the trans. I was so sure that it was oil on the disk and there was no question in my mind.

I'll probably have to call RPS to figure out the correct step height on the flywheel. When I bought the clutch it came directly from them with a flywheel, so I assume it at least WAS correct at some point.

I could tell the clutch was slipping cause RPMs would climb way past the rate of actual acceleration. It came on REALLY fast too, which makes me wonder if it wasn't just the engagement.

I guess I'll try and get the specs, measure it all, and then throw it back together to check disengagement...durrr

Thanks again guys.
 

Terry Posten

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Joined
Dec 16, 2003
Messages
9,009
Location
Davenport, Iowa USA
IIRC, the stock step is .610-.620.

Clutchnet said that was perfect for there discs.

But your right Jeff, you would think if you bought a complete set, it would be ready to drop in.
 

mitsuturbo

Well-known member
Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
I hate to state the blatantly obvious here, but are you sure you dont have a busted center diff, axle, or something else in the drivetrain?
The last time i saw someone post a problem like this, it turned out to be a busted rear axle stub. (a week or 2 ago)
 

grocery_getter

Well-known member
Joined
Jun 20, 2004
Messages
1,225
Location
Kent - industrial suburbs of Seattle, WA
Holding everything the same, a shallower step will resist slipping better and make the clutch last longer but harder to disengaged. A deeper step will make disengagement easier but will slip easier and will not last as long.

Quoting Terry Posten:
IIRC, the stock step is .610-.620.

Clutchnet said that was perfect for there discs.

But your right Jeff, you would think if you bought a complete set, it would be ready to drop in.

 

jepherz

Staff member
Joined
Aug 8, 2004
Messages
7,877
Location
KC, Missouri
^^Yes, even with the same pressure plate.

Thanks again for the help guys. Yes, I'm positive the 4wd system is working as intended. I haven't had a chance to measure anything but will try to next week.
 

i think you mean harder to get into gear. you may have to push the clutch in farther if the step is machined wrong but pedal pressure stays the same with the pressure plate. the clutch may never fully dissengage due to the wrong depth making it hard to put into gear.
 
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