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I've had a clutch chatter problem with my 66,350 HP roadster. I've replaced the clutch, pressure plate, throw out bearing, pilot bushing, and flywheel and additionally balanced the flywheel and clutch disk together before installation. I used a Hays clutch assembly as my replacement. After reinstallation, I still have the chatter problem even after many break-in miles. Disassembly a second time and replacing the Hays clutch assembly and reassembly has not remedied the situation. Can anyone help me with this problem? Additional information I can provide: There seems to be some end play in the crankshaft(.010) and the input shaft on the transmission seems to be tight(no back and forth movement).
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Re: Clutch Chatter
Angelo,
Do you eperience the chatter only in first gear when starting from a dead stop or when changing all gears?
Also, does the chatter go away once you are moving and have fully let out the clutch?
Chris -
Re: Clutch Chatter
Chris,
I experience the clutch chatter when I start from first gear and it goes away once I'm moving along. Also, when I down shift, and let out the clutch, it doesn't appear to be smooth. I hope this helps you.Comment
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Re: Clutch Chatter
I've had a similiar experience with a clutch on a new car. After many frustrating attempts by the dealer and myself to correct the problem (along with accusations to my wife for riding the clutch) and years of "living with chatter" I found the original flywheel had a runout of over .050. I never suspected the flywheel because the surface looked great, so I never had it checked/resurfaced. It was surfaced from the factory that way (error)
probably due to something under one edge during the original machining process. Did the clutch ever perform smoothly? Did you have the flywheel surfaced? Are you careful to keep the clutch clean during reassembly?Comment
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Re: Clutch Chatter
Steve:
The flywheel was resurfaced(and I assume the runnout was checked) and balanced with the clutch assembly(pressure plate). The clutch disk was very clean when installed.
AngeloComment
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Re: Clutch Chatter
Classic symptoms of a bad engine mount or separated transmission mount - worth a look, and the parts are cheap.Comment
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Re: Clutch Chatter
After 40 years, some old GM flywheels have been surfaced too much. I'm sure you noticed that the 6 pressure plate bolts were shouldered. If your flywheel is now too thin, these bolts may be bottoming on the shoulders when you torque them down. This would allow the pressure plate to move a little while the clutch is slipping, causing the chatter.
I will also go out on a limb and say that you should go back to a OEM type diaphragm pressure plate and disc. Most of the Hays clutches are built with higher than stock griping force. This, along with an aggressive disc facing, would increase the odds of chatter. GM doesn't sell a 10.4" clutch anymore, but you can get a new one from an auto parts store like NAPA or Carquest.
I wouldn't try any "rebuilt" unit - they tend to chatter too.Comment
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Re: Clutch Chatter
All the responses are valid, and it could be a combination of several of these causing the problem.
FWIW, let me also throw in another possibility: too much overall slack in the drive train. Slack can come from the looseness of the pressure plate on the trans input shaft, slack inside the trans itself, the fit of the driveshaft yoke on the trans, all the u-joints if worn, and the lash of the ring and pinion. If all of these points have some slack (and they all do) when you add it all up it may be enough to cause whipping or vibration of the drive train as the clutch begins to take hold. Thrown in some extra motion from worn or loose mounts as John has mentioned, and you get the "shakes".
How much is too much? Who knows. I can imagine a good "tight" drive train having smooth clutch engagement (assuming of course that the flywheel, disk, and pressure plate are running true), and at the other extreme I can imagine a very loose drive train having rough engagement.
Just a theory.Comment
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Add-on
Original GM flywheels have a 'wear indicator' (beveled edge) to indicate when their useful life is over. No machinest worth his salt should resurface a flywheel that's getting close to being used up. But, this can be verified by dropping the inspection cover and viewing the outside edge of the flywheel to assess how much bevel is left on the edge adjacent to the machined surface--better be a BUNCH of exposed bevel there; say 1/4-inch or more....Comment
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Re: Clutch Chatter
Hays and other "hot-rod" clutches (like "Zoom", etc.) aren't known for smooth engagement or reasonable pedal pressure. My experience says to stick with good diaphragm clutches like LuK (largest clutch manufacturer in the world) or Centerforce. Have used lots of both, have never had a problem with any of them.Comment
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