'61 Muncie M20 Noise

[Larry B.]

I have an M20 in my '61. After the car is warm and has been run for a while, I will get a loud rattling sound coming from the trans that only lasts for a couple of seconds and goes away. The rattling and be felt through the shifter and usually occurs when coming to a stop or idle. Occasionally, I have a problem not being able to upshift or downshift into second gear. I don't know if this may be related.

Because the noise only lasts for a couple seconds and is so intermittent it is hard to figure out where the problem is. Any ideas what this may be? Any problems with driving the car in this condition? Thanks!

[Jerry G.]

Re: '61 Muncie M20 Noise

Forks or syncros, open it up. it's not hard to fix.

[Domenic T.]

Re: '61 Muncie M20 Noise

Larry,
Munci cluster gear had a plate riveted to the front of the gear to eliminate the chatter.
Not all muncie's had the plate.
They would chatter more when the lube warmed up and got thinner.
Your 2nd gear problem could be a number of things such as worn syncro, linkage adjust, or even thick & cold lube (mostly in the winter).
Usually if the gear syncro is bad it will grind going into gear and pop out of gear when you let off the pedal.

DOM

[Larry B.]

Re: '61 Muncie M20 Noise

Is it ok to drive without the rivets? Any other way to diagnose without pulling the trans apart?

[Domenic T.]

Re: '61 Muncie M20 Noise

Larry,
Yes it OK to drive without the riveted plate.
The plate was a mod to stop the chatter and was a later addition.
It was about 1/16 thick, Riveted on the front of the cluster and had a interferance fit against the input shaft that kept tension on it.

DOM

[William C.]

Re: '61 Muncie M20 Noise

What muncie do you have? What casting? the spring loading started in '66 as best I can tell, for sure never saw a small pin version with the feature.

[Larry B.]

Re: '61 Muncie M20 Noise

I have a '65 Muncie 1325 case.