M-22 muncie

jus4funn68 · May 14, 2003

Hey Guys, Has anyone heard of muncie producing M-22 transmissions WITHOUT the straight cut 20 degree gears? Someone told me that all M-22's were not "rockcrushers" I thought they were all the same. Kevin
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68 SS 396/375 L-78

Spames · May 14, 2003

All M22's are "rockcrushers".

However, an M21 has the same close ratio, but DOES NOT have the straight cut gears.

Sounds to me like this is the source of the confusion in this individual.

elcamino · May 14, 2003

The M22 was a heavy duty version of the M21

M20 - wide ratio
M21 - close ratio
M22 - HD close ratio

Supposedly the M22 could take more abuse do to the design of the gears but noise was the big drawback and thus the name rockcrusher because thats what it sounds like is happening inside the trans.

I agree, one type type of M22.

stingr69 · May 14, 2003

No Muncies have straight cut gears. The helix angle is less than the 45 degrees on the M20 and M21 but still not straight cut.

The best assumption I can come up with about why they are referred to as "rock crushers" is that the design of rock crusher gears uses a higher design factor as compared to other types of geared transmission machinery. The lower helix angle allows gear sets to be stronger for the same pitch diameter, ratio and gearbox size. If you ever take a look at a gear design handbook you will see what I mean as rock crushers are specificaly mentioned. Nobody knows the answer for sure. Just folklore I guess.

-Mark.

jus4funn68 · May 15, 2003

I agree stingr that they are not truly "straight cut" gears, just that is what some call the 20 degree gears as opposed to 45. Thanks for the info guys, I didnt think muncie ever made an m-22 with 45 gears but that is what i was told and they were very strong in their belief. I appreciate the feedback. Kevin
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68SS 396/375 L-78

ratchetmaster · May 15, 2003

I believe the name "rock crusher" comes from a nick name given to it because it sounded like a bunch of rocks being crushed inside it.

Back in 1975 I remember talking about this with my race buddies one night before our street races.
My friend had a 69 with the M22 and we were all talking about it.

in 1971 (?) a new HD M20 was made which looks a lot like an M22 on the outside (turbo 400 size tail shaft, fine spline front shaft) but as you know the early M22 trans looked a lot like the 20 and 21 with a small shaft and coarse spline front shaft.

Anyways, "rock crusher" to me always meant the M22 bacause of the noise they made.

Guido67SS · May 16, 2003

http://www.5speeds.com/cgi-bin/Ultimate.cgi?action=intro

http://www.autogear.net/m22ratios.htm

http://www.gearzone.net/muncie3.htm

http://www.garagemotorsports.com/muncie.htm

All u ever wanted to know bout Muncies. I broke to much stuff and finally got smart and out a th-400 in it.

http://camaroz28.cardomain.com/id/guido67ss

Guido

jeffdoughertysr1 · Jun 17, 2022

I've got a 67 RS 350 car that I've put an M-22 into. It's the "660" case real deal Muncie.
We're there RS/SS cars made with M-22's in them or no??

jwbavalon · Jun 18, 2022

The heavy-duty M22 was limited to just the solid-lifter engines, starting in Camaros in 1968.

Melmount · Jun 18, 2022

People confuse the hd m21 fine spline 1070-74. As an m22 quite Often.

M-22 muncie

jus4funn68

Spames

elcamino

stingr69

jus4funn68

ratchetmaster

Guido67SS

jeffdoughertysr1

jwbavalon

Melmount

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