67 Rebuilt M20 Noises - Bugging Me!!

[Jace H.]

My rebuilt M20 is making occasional grinding noises when I shift down in the lower gears and hold the clutch in for a few seconds (can feel it with my ****ch foot). I also here a slight whine in 1st thru 3rd gears when the car is cold (goes away after a long drive). I had much worse whining noises when I first got the tranny back so we yanked it and replaced a pitted 4th gear. So now I am down to these occasional grinding noises and the faint whine. Is this normal for a rebuilt tranny that was rebushed (is that a word)? I have been told that it is normal and that the tranny will eventually loosen up and the noises will fade away? I am most concerned about the occasional grinding noises I think I can live with the whine. Thanks in advance for any insight.

Jace Holt
#28944

[Verle R.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Jace,

Muncies whine. The Muncie in my 65 whined when it was new. The Muncie in my 69 whined when it was new. The Muncie in my 65 still whines.

Please expand on the grinding noise. Does it grind as you are putting it in a lower gear or after it is in gear? Does it grind when shifting up through the gears?

Regards, Verle

[Jim T.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Jace did I read your msg right in that after the transmission was rebuilt it was making noise and the rebuilder used a pitted 4th gear causing you to have the muncie removed and 4th gear replaced? Wonder what other parts were not replaced like synchronizers?

[Jace H.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Verle,

It does not grind when I shift into any gear only when I have shifted and hold the clutch down. No grinding as I shift up or down. Thanks for your help. This car runs flawlessly otherwise and I just want too eliminate this noise. I can live with the whine.

Thanks,
Jace

[Jace H.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Jim,

When we had the tranny apart this last time we did replace the 4th gear synchro as well (the brass ring) as it had worn as well. We looked it over good and found everything else to be fine. Beware of Ron's Transmissions in California as he is the one that rebuilt the tranny and put the used 4th gear in there. He is flaky to work with if you have a problem.

Thanks,
Jace

[John M.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Jace,
I rebuilt a muncie for my 69 and it whined a little more after then before. Maybe the new parts? Anyway that grinding with the clutch in sounds like a throwout bearing problem. That's when the load is on the bearing.

[William V.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Jace

Check the clutch adjustment.

To check the clutch adjustment, at a stop in neutral with the clutch up, push the clutch all the way to the floor and then shift into any forward gear and then into reverse. If it grinds in reverse, the clutch is not fully disengaged and a minor clutch adjustment is needed. Keep in mind that a properly adjusted clutch has a little top peddle free-play and fully disengages when depressed.

To test the synchronizers: At a stop in neutral, with the clutch up and properly adjusted, you should be able to depress the clutch and shift into any forward gear without a grind. If there is a grind in any gear then there is probably a synchronizer problem related to the gear that grinds.

[Jace H.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Bill,

I will do your checks and report back. Thank you very much for the tips.

Jace

[Jace H.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Bill,

I tried your test and in each case there was no grinding. I drove the car last night and was able to get it to grind when shifting down and holding the clutch in as I initially reported. It seems to be less frequent but is still there. I feel a flutter in the clutch pedal. Any other ideas???

Thanks for the help,
Jace

[Michael D.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Sounds like a throw-out bearing as John stated. If it only "grinds" with the clutch pushed in. Was the throw-out bearing changed when the trans was rebuilt?
Mike D #1787

[Jace H.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Mike,

Throw out bearing was replaced when the trans. was rebuilt. If it is the throw out bearing won't it get worse over time and become obvious? Should I just wait and see?

Thanks,
Jace

[Michael D.]

Re: 67 Rebuilt M20 Noises - Bugging Me!!

Jace,
From my experience with a bad throw-out bearing it does get worse and it does take time to get worse if you don't drive the car every day, but when you mentioned that you felt a flutter in the pedal that is what happened to one of my cars. The bearing did go bad a few weeks after installation. I drove the car 50-100 miles a day. I don't remember exactly what happened but the bearing was the wrong size or not the right type for the pressure plate "fingers" of the pressure plate I was using. Also, I used to rebuild my own tranny's and they did whine abit when they were rebuilt, if something was going to happen it usually happened early after the rebuild. After a while the whinning didn't bother me much, you get use to it. I hope you figure it out soon.
Mike D #1787

[Jace H.]

THANKS - Mike *NM*