Clutch Chatter or Shudder

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ptrmzr

Well-known member
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Jan 2, 2012
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Location
NJ
My Car
1971 Mach 1 351C 4V 4sp 3.50L
I have been getting some serious clutch chatter so I pulled the trans to inspect the clutch and I found it to be brand new like the seller described. I broke the glaze on the flywheel with some emory cloth, replaced the badly worn pilot bushing and thinking that was the likely cause I put it all back together.

It's still chattering, but if I put on the e-brake and try to pull away no chatter.

So I disconnected the drive shaft to feel for backlash in the differential. In checking the rest of the drive train I noticed some play in the differential input shaft. It doesn't seem too excessive but I am wondering if this much play could cause a harmonic that becomes a chatter in the clutch:

spacer.png
th_IMG_6735.mp4'%20alt='th_IMG_6735.mp4'


Your experiences?

Thanks,

Peter

 
Check for:

- Broken or weak leaf spring(s)/bushings

- Weak trans mount or motor mount(s)

 
Did you check the pressure plate? Was it new or glazed or heat checked? If it doesn't engage evenly it can cause chatter. How were the splines on the input shaft? Worn splines can cause too much slop and grooves can keep the disk from engaging smoothly. They also need a very light coat of grease. Was there any evidence of the disc hub rubbing on the flywheel or pressure plate?

 
I have been getting some serious clutch chatter so I pulled the trans to inspect the clutch and I found it to be brand new like the seller described. I broke the glaze on the flywheel with some emory cloth, replaced the badly worn pilot bushing and thinking that was the likely cause I put it all back together.

It's still chattering, but if I put on the e-brake and try to pull away no chatter.

So I disconnected the drive shaft to feel for backlash in the differential. In checking the rest of the drive train I noticed some play in the differential input shaft. It doesn't seem too excessive but I am wondering if this much play could cause a harmonic that becomes a chatter in the clutch:

spacer.png


Did you see any sign of the clutch ever having oil/grease on it? Is this a new problem? Chuck
Click to expand...
 
I tried starting off in the driveway with the hood open so I could see the air cleaner, but it moved very little with respect to the rest of the car during the chatter. The shifter also didn't shake much all telling me that the motor mounts aren't totally shot.

The leaf springs are weak and the rear end sags. It has air shocks to keep the rear end at the right height. The input shaft splines are in good shaped and lightly greased.

I have to take a closer look at the springs. Maybe it's time to bite the bullit and change them out.

 
I would look at the drivers side motor mount and the overall condition of the clutch linkage.

 
The reason that I mention mounts is that I had a Jeep CJ that would exhibit bad clutch symptoms when leaving from a stop. Replaced all 3 mounts (RH and trans were visibly bad) and symptoms disappeared. In my case, yes, the engine and trans tailshaft flopped all over the place before replacement.

Funny part about it was the Jeep had an automatic in it.

Shuddered just like a bad clutch.

Maybe the rear springs could be wrapping up a bit if broken or weak, IMO.

I'd verify U-bolt tightness and spring center pins while you're at it, too.

I always try to eliminate the "free" stuff first before throwing $$ at it. If you do want to test for a bad trans or engine mount, you can rig a small ratchet strap or motorcycle tie down to temporarily snug it up for testing. Do one "plane" at a time (engine to crossmember or trans tailshaft to crossmember), but not both at the same time in order to isolate the offender.

Just a thought.

 
Last edited by a moderator:
Is your chatter just when puling away in 1st, or is this when engaging each gear?

I've got a similar problem in mine in that I get clutch judder when pulling away in 1st. Nothing at all engaging 2nd, 3rd or 4th and downshifts are also smooth.

Mine's going into a workshop next week to be looked at and, if it helps, I'll post the diagnosis here.

 
Thanks everyone for the great suggestions and things to try! Bellini, it only occurs in first, but what I forgot to mention is that it also shudders when I down shift...when I let the clutch out slowly when shifting from 3rd to 2nd say. I would be very interested in hearing what you find out with yours.

 
Last edited by a moderator:
I've just had the report back on mine from the specialist I took her to a few days ago.

Now, the following is by no means conclusive, but it's as far as they're going for now until she's been roadtested.

They've found the prop is out of balance and the UJ's are worn, plus there's some wear in the transmission bushes. All are being replaced and the prop will be re-balanced.

We'll see what diffference this makes to mine, but it won't be untl March next year as there's a fair amount of other work I want done and the specialist is pretty loaded with other customer projects.

 
I've just had the report back on mine from the specialist I took her to a few days ago.

We'll see what diffference this makes to mine, but it won't be untl March next year as there's a fair amount of other work I want done...
Click to expand...
do you mean other work like getting rid of the wrong vacuum can and curving the ignition advance?



I have been getting some serious clutch chatter so I pulled the trans to inspect the clutch and I found it to be brand new like the seller described. I broke the glaze on the flywheel with some emory cloth, replaced the badly worn pilot bushing and thinking that was the likely cause I put it all back together.

It's still chattering, but if I put on the e-brake and try to pull away no chatter.

So I disconnected the drive shaft to feel for backlash in the differential. In checking the rest of the drive train I noticed some play in the differential input shaft. It doesn't seem too excessive but I am wondering if this much play could cause a harmonic that becomes a chatter in the clutch:

spacer.png
th_IMG_6735.mp4'%20alt='th_IMG_6735.mp4'


Your experiences?

Thanks,

Peter
Click to expand...
if it chatters when you release the clutch slowly from a stop iy is the clutch 99.99999 percent of the time . . lots of new clutches chatter because they are simply c__p . . people think that a 100.00 clutch kit is a high quality piece that will work just as good as a 350.00 clutch or even the more expensive ones are often junk . . i would just yank it out and buy a real clutch like a mcleod 3 finger pressure plate with 1650 pressure for stock engine or 1650 for a higher perf one and and centerfoprce basic street disc . . call summit to get it . . it is not in their catalog search.

.

.

 
Last edited by a moderator:
If the previous owner had a rebuilt clutch and pressure plate installed, use it as a core and buy brand new. Also, the flywheel should be reground and balanced.. when there is chatter on take-off, it's usually and indication of a bad clutch and pressure plate.

When a clutch is engaged under power, it should be smooth and steady. I can tell you that pressure plates can warp and clutch springs can have uneven tension.. A diaphragm clutch can distort with heat.

 

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