Hello all, I'm new to the forum; however, I have been following the posts for some time now. I am hoping to get some insight on a problem that I am seeing with my new C6. When the engine is at high RPM's the clutch begins to fall to the floor. To be more precise, it requires very little foot pressure to disengage the Pressure Plate. An example maybe more relevant:

When under heavy acceleration and high RPM, the clutch pedal will already be at a point where it is almost to the floor. Spring tension would still see the clutch in an outward position; however, very minimal foot weight will push the clutch down to the point where it disengages.

I went to my friendly GM dealer and they had their Corvette guy confirm that... "Yeah that's definitely not right" only to have a call from the controller to say "It is normal operation of the C6 clutch mechanism" . They did humor me and let me REV a new C6 on the lot in Neutral and it did indeed exhibit the same characteristic. My thoughts are, even if this is the same on most Corvette's, it's still wrong; the pressure plate should not lift under high RPM. Once cars begin getting a few miles on them the clutches will begin slipping and that will really suck. GM's take on it is "If it's not slipping then we cannot do anything about it"

 

The clutch is a LITTLE bit lighter at higher RPM's but it shouldnt be Mushy..

 

Does that mean everyone has this problem? With a couple of mods one would think that slippage will become a problem. I custom built my last car (over 400hp) and it had no problem with pedal drop or RPM related problems and my last car rev'd will above 8000 RPM, the C6 is only 6500RPM. A car that cost over 55k should have a pressure plate that does not lift under high RPM's. Even if it is not slipping now, I imagine that it would when the clutch material gets a little thinner.

 

 

I will assume by the lack of responses one of three things. That I am either alone with this problem and GM is full of ; Everyone does indeed have this same "charecteristic" with the cars but do not want to tell other forum memebers about it; or the people who have read this post drive there cars like Hyundai's and don't have to worry about this being a problem.

 

This just happend to me. Is this the same thing.

Today, took the car for a ride. I was driving for about 30 min or so. I got on the expressway. Went through WOT 1st, 2nd then proceeded to 3td so I thought. I did not miss 3td but the clutch was stuck to the floor. When I let off the gas it poped back up. What would cause that to happen? Is that a common thing with a clutch. I have had only automatics in the past so I do not know if this is normal. I have 2,700 mi on the car and never had this happen before.
Thanks,

Ted

 

My clutch does not actually stick or stay too the floor, but rather by the time I hit redline there is very little travel left on the clutch pedal. With that said the problem you are seeing could probably become more prominant on all cars as time goes by, that is my concern. If you go to GM they are proably going to feed you the same BS they fed me "This is normal"... Total B.S dude

 

I am pissed. How the fu** could they think that would be ok. You have a redline and you can't even come close. I will call my dealer on Monday. At least I will alert them of a potential problem if something breaks.

 

You may be correct. I was able to shift to 3td. The clutch did not come back out until the rev's dropped.

 

I had this problem to ,the clutch will stay down tell I release my
foot from gas puddle.Its also combined by bad smell like burning rubber,
I beleive its a clutch smell.

I think GM made the clutch that way may be to protect the drivetrain.....!!! or could be part of TM.

GM should of used good quality parts and avoid such mechanical or electronic interference that limit driver control and involvment.

omar

 

 

The hydraulic linkage will automatically compensate as the clutch disc wears.

What all of you are seeing is a result of the decision to design the release levers for the clutch so that centripetal force will lighten pedal pressure. There are three ways the clutch arms can be designed, so that pedal pressure increases with increasing RPM, so that pedal pressure stays the same with increasing RPM, or so that pedal pressure decreases with increasing RPM. Chevy chose the latter. This characteristic allows the clutch to slip under shock loads (powershifting) at high RPM, and protects the drivetrain.

I'm not saying it is the right choice, but they thought it was. Anyway, if you don't like it, simply change out the clutch for one with a different characteristic. RAM makes a clutch that has an increasing pressure with increasing RPM characteristic.

 

Shodog,

Do these various types of clutches have model or nomenclature that identifies how they react to higher RPM's.

Any idea about warranty implications?

 

Shopdog,

sorry for the misspelling - my wife was giving me instructions at the time

 

No way is the clutch pedal staying down normal operation. The clutch should come back all the way when released at any RPM. Please post what the dealership found. I'll have to see if their is any change in effort, but I don't think there is.

Nick

 

c6nut,
The problem you describe sounds like one I experienced a few years ago while hammering my 6spd Z28 down the dragstrip. On a run to redline and a hard shift, the clutch pedal stayed on the floor. At first I thought there was a real problem, but I realized that part of the clutch pedal was actually getting hung up on the floormat. Hopefully there's a simple explanation to your problem-

 

Okay, I just got a call from GM stating they found a problem that may affect some drivers of the 05 vette. GM did indeed design the clutch to be a lift type clutch that lightens the pedal pressure under high RPM’s; this was to make the car more drivable and to lessen he pedal effort. I imagine that this would be okay for 90% of the people driving the vette, because they don't drive there cars aggressively. So it appears I am correct, the pressure plate is too light for aggressive driving. GM will be replacing my clutch next month with a completely redesigned clutch, longer fingers on the PP and a stronger clamping force. The GM rep was unsure, but speculated it was the part number for the 05' Z06. This should be good news to some of the people here on this forum.

 

Holy Cow! I'm very surprised that they would approve anything other than putting original parts back in. This is good news Please update us with part numbers and /or TSB if they issue one.

 

C6 NITPICKER:
Who called from GM? I have the problem of the clutch pedal sticking to the floor @ WOT if you spped shift the car. Needless to say it's an issue. The trans goes into gear but it just stays at the rev limiter until you back off the throttle. At first I thought I just missed a gear, but realized what happened after gathering my thoughts. Of course it was the first time I ever ran it hard. Obviously this is a problem probably with most C6's. With a rather softly sprung diaphragm pressure plate I have seen this in the past. If the clutch was manually adjustable you could adjust less travel in the release bearing so it wouldn't go over center. I think the going over center might not be the issue since some folks are having the clutch travel already lessen with rpm. Any info about anything GM is going to do would be greatly appreciated.

 

My dealership here in San Jose Ca told me that he had a call from some of the GM boys in Detroit telling him that a new clutch is in the pipeline for the 05 Vette. He was researching for my problem and this is how this all came about. In the mean time I imagine the GM will handle this kind of thing on a case basis. It might be a good idea to keep a lid on it until things are smoothed out. If everyone goes to the GM dealer and says "I heard blah blah and I think.... so I want my clutch changed" even if they don't have the problem or sense it. This might make GM more reluctant to help those of us that will truly use/need the different clutch setup. This was a similar situation with the Honda Preludes(SH) a few years back (and no I don't own a Prelude) with the ATTS(similar to active handling), they found that with certain aggresive drivers there ATTS system, the wheel clutches, would break and the system would need to be serviced So they redesigned the ATTS and only replaced the unit only when someone would have repeated failures.