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Topic: Clutch clunking :-(

in Forum: C3 Driveline Components


Clutch clunking :-(

Posted: 6/14/10 2:15pm Message 1 of 7
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Joined: 3/3/2010
Posts: 94
Vette(s): 1968 convertible

I have maybe 40 miles on my new clutch (and rebuilt engine) in my 68.  I drove it and the clutch seemed fine for several short drives – then out of nowhere I get a clunk and first gear sort of pop’s out with the clunk and pulling away is difficult.  After the car cooled down – it seemed fine?

 

I pulled her out again and went for a 10 mile drive, sure enough – somes result once things got good and hot?  I went home jacked her up and her my boy push in the clutch – its clearly something inside the bell housing.  Once it cools down it no longer does it?  Any thoughts ?  THis is a Ram clutch and throw out bearing if that's important.

 
I think this weekend I need to pull the tranny and inspect the noise....ugh ! 



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Clutch clunking :-(

Posted: 6/14/10 6:53pm Message 2 of 7
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York, PA - USA
Joined: 5/18/2010
Posts: 1518
Vette(s): 1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top
It sounds like something could be wrong with the clutch but also check the linkage and make sure it doesn't need adjusted..that is usually what makes them pop out of gear..could be the clutch is not completely "off" when pushed in..I have had that when it gets hot..makes the clutch engage at the floor and won't allow full disengagement..



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Clutch clunking :-(

Posted: 6/14/10 8:06pm Message 3 of 7
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Do you hear this "clunk" just pushing the clutch down, without the engine running? If so, I can think of a couple of things that can make that noise. First is the TOB(throw out bearing) is not installed properly on the fork. The fork has two thin, flexible "fingers" on the back of it. A LOT of people think the TOB is supposed to go between the fork and those fingers, but its NOT. Those fingers should be inside the groove on the bearing. If the TOB is installed incorrectly, is will usually "pop" every time the clutch is mashed, and it will also not pull the TOB all the way back to the released position, which leaves it running against the pressure plate all the time.
Another possible cause for the noise is the fork pivot ball. If it, or the fork is worn severly, it will also pop when pushing on the clutch.
Neither if these things will cause the trans to pop out of gear, however, unless the clutch is just not releasing fully, and you're not able to get the trans fully into gear. I don't have a clue as to why it will only do this when it gets hot....unless you've installed a hydraulic clutch on the car...you haven't done that, have you?



Joel Adams
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Clutch clunking :-(

Posted: 6/15/10 3:18am Message 4 of 7
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Joined: 3/3/2010
Posts: 94
Vette(s): 1968 convertible

I have had a suspicion it was the throw TOB, I never installed one before and when I removed the old fork from the bell housing the TOB dropped out – I never had the opportunity to inspect it for reverse engineering purposes.  

 

However, why would this issue only happen when the car is hot? Once the car cools down – no more clunk (or pop).  No hydraulic clutch here.

 

The car engages and disengages the clutch completely.  However, during engine timing I bent my tach cable and it broke.  I just replaced it so since installing the new engine I am not familiar with the engine RPM’s.  But I was running nearly 3K at 60 and I suspect that the clutch might be slipping.  

 

I can’t recall how I installed the TOW, so it sounds like I will be removing the tranny this weekend.  When I installed the trans I needed to depress the clutch in order to get the tranny to bolt up all the way– is that OK ?

 

Anyone have a picture if how the TOB sits in the fork?

 

At least I don’t have to remove the bell housing (minor time saver I guess)




Clutch clunking :-(

Posted: 6/15/10 4:07am Message 5 of 7
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Bloomfield Hills, MI - USA
Joined: 6/29/2008
Posts: 199
Vette(s): 1975 Corvette coupe, 4 speed manual, 383 ci 9.5:1,Edelbrock dual plane Air Gap intake, Alum Heads,Comp Cam, roller Rockers, PS,PB,Tilt
i have a full set of instructions PM me with your email and I will send them tonight


Clutch clunking :-(

Posted: 6/15/10 4:26am Message 6 of 7
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Vette(s): 1968 convertible
Thank you JP - sending a PM now.
 
Do you think its the TOB ?  given then it only does it when its hot?



Clutch clunking :-(

Posted: 6/15/10 10:20am Message 7 of 7
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
[TUBE]e4e8P0fFltk[/TUBE]

This should help.
I still don't know why it would change the way it works when it gets hot....it just doesn't make sense to me at this point....I'm missing something.



Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

in Forum: C3 Driveline Components


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