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Vibration in the clutch pedal, and clutch doesn't fully disengage. What's wrong?

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Old 07-01-2016, 05:49 AM
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Default Vibration in the clutch pedal, and clutch doesn't fully disengage. What's wrong?

So went to the track last night and after my last pass I noticed the clutch pedal had a vibration in it. Seemed more noticeable at higher RPM's. With the car at a stop, the clutch pedal on the floor and the car shifted into first gear, I tried reving it to 3500 RPM and the car started to move forward, so the clutch is not fully disengaging. When it was in gear and driving normally there seemed to be a little noise at higher RPMs as well.

I am not a transmission expert, so don't know what's going on. Can anyone point me in the in the right direction?
Old 07-01-2016, 07:20 AM
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Verify clutch fluid level is OK
Verify clutch fluid is not overly dirty, if so replace it.
If neither of those are the issue, start taking things apart.

The TOB on these cars sits in the PP retained by a snap ring. The clutch fork could have rolled over the wall of the TOB and not allowing it to fully release the clutch.

Here are some reference pictures when I had mine out:

You can see the TOB and TOB retaining ring








OHHH if you are going to take the clutch out...make sure you PULL DIRECTLY OUT on the clutch fork to release it from the TOB. Otherwise you will never be able to pull the trans out and you will beat your head against the wall.

This was the first car I had that was like this. My hydraulic system on my 04 GTO, the TOB was bolted to the trans and came out together.

I just realized you have a 900+hp setup LOL What clutch are you running? Does the clutch act up when car is fully cool? It may be a heat issue trying to hold that power.

Last edited by smitty2919; 07-01-2016 at 07:38 AM.
Old 07-01-2016, 09:16 AM
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I have a MCCloud Street Twin. It is new, was properly broke in, and doesn't slip. It still grabs fine. But if I don't get the problem resolved with it not fully disengaging, it will wear itself out prematurely.

The issue happened after a run down the track. I let the car sit for about 45 minutes after the run. Then I drove it home about 80 miles. Did the same thing the whole way home. Not sure if it "fully" cooled off or not.
Old 07-01-2016, 10:12 AM
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can you adjust the MC that came with the street Twin out further to allow more stroke so you have disengagement?

with that said if the clutch set up was working well before and now you have disengagement issues I would look closely at the fluid condition and the MC & slave for any possible leaks.

My ST came with a 13/16" MC (larger bore than stock MC) made by wilwood. Very good clutch...but at your HP maybe you did hurt it and a disc warped from heat.

I had good response from McLeod tech before and had them also rebuild my Twin
Old 07-01-2016, 11:09 AM
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I can adjust the pedal and may try that. I'll also check the fluid level and its condition.

I will be away from home until tomorrow morning so I can't do anything anything until then.



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