I have a 1972 Oldsmobile Cutlass Supreme with a Rocket 350 and a Muncie transmission with a 4 speed Hurst shifter. After driving the car long enough to get it fully warmed up I get a chatter in the clutch only when in reverse. Does anyone know what may cause this and how to fix it. I have had a new clutch kit installed but that did not help.

 

from time to time the flywheel needs to be resurfaced.

 

Does the car have a limited slip differential? Backing up in a nearly straight line? Is this occurring while the clutch is fully engaged OR when it is being engaged?

 

Not resurfacing a flywheel is like replacing brake pads and using the old worn rotor surface. Its a gamble and never recommended.
Check out this info:

https://www.google.com/search?client...5NoPiO2Q4Ac_28

http://farmmachinerydigest.com/groun...ng-a-flywheel/

 

The car does not have limited slip. It happens backing in a straight line when clutch is being engaged

 

Rules out limited slip clutch chatter. Was the flywheel resurfaced during the clutch replacement? Motor mounts good, particularly the right side?

 

I read somewhere that the M20 4 Speed with the 3.08 rear end was **** to reverse chatter while engaging ...
My does - so I work around it with decent results (just a little extra slip to get the car moving then back off and then fully engage +-) lol your results may vary

 

Thanks! Does this ever happen in first gear? Seems it only happens in reverse for me.

 

Just reverse for me

 

I'll throw my 2 cent in. I'm going with a high gear ratio problem and as @Cosmic Charlie mentions, it needs more rpm and slip. I heard somewhere that reverse is similar in ratio to 2nd, but I have never looked it up nor counted teeth.
I had that problem with a Spec stage 3 sintered bronze disc and a Centerforce dual friction. I have not experienced it since switching to a McLeod twin disc RST all organic..... just some things to chew on.

 

Here's what I have on Muncie reverse ratios. Reverse is a bit steeper than first gear.

1963-65:
M-20 Reverse ratio 2.64
M-21, 22 Rev ratio 2.27

1966 on:
M-20 Reverse ratio 2.59
M-21,22 no change from 63-65