m22 how to tell from m21?
 

i've asked this before. never got a solid anwser. casting numbers etc.. fine spline- coarse! most guys say they have to look at it. what do you have to look at? gear has to be 20 degrees or 30? anyone! thanks

Re: m22 how to tell from m21?
 

Most of the time the easiest way to tell is a M21 has one ring around the input,whether fine or coarse spline. The only problem is if the input was changed it may not have a ring. Then you must check the gear angle M22 are 20 degree m21 and m20 are 30.

Re: m22 how to tell from m21?
 

what should the gear angle be? thanks

Re: m22 how to tell from m21?
 

Added that above as you were responding..

Re: m22 how to tell from m21?
 

I called a buddy out in California who rebuilds these all the time and here's what he told me, please excuse me in advance if something was lost in the translation:

On 1966 and newer muncie transmissions, the input shaft on a M-22 did not have a ring around it. M-21's had 1 ring, M-20's had 2 rings. This is of course is assuming the input shaft is original to the trans.

On the passenger side of the main case of the trans, there should be a C-code somewhere near the v.i.n..

Inside of the trans, the gears are cut at a straighter angle.

M-22's could have been fine or course splined.
The fine splined ones were produced between 1971 and 1974

any questions or need help rebuilding your trans call Craig Wright of "The Wright Connection" @ 661-304-1967

Re: m22 how to tell from m21?
 

M22 transmissions built late Oct of 1968 had a C designation following the build date. Those transmission built prior did not have that identifier so the easiest way would be to look at the input shaft. M22's had no grooves on the input shaft. M21's had one groove on the input shaft and M20's had two grooves. Fine spline was used in later years and was not a transmission type identifier.

Re: m22 how to tell from m21?
 

[ QUOTE ]
On the passenger side of the main case of the trans, there should be a C-code somewhere near the v.i.n..

[/ QUOTE ] If a C case is rebuilt using m20 and m21 replacement gears ,it will appear as if its an m22 until you open it up so that is not a great indicator oif whats inside,also fine splines started in late 70 model year not 71. The easiest rule of thumb is if it has rings it isnt an M22,otherwise you need to see the gears to be sure.

Re: m22 how to tell from m21?
 

[ QUOTE ]
M22 transmissions built late Oct of 1969 had a C designation following the build date. Those transmission built prior did not have that identifier

[/ QUOTE ] Steve, M22s used the C in 1968 date production[69 model year]

Re: m22 how to tell from m21?
 

my buddy just bought a rebuilt m22 from a guy in ct. real good price. 20 degree angle gear.

Re: m22 how to tell from m21?
 

Ct. ???? huh, isn't that where 427King lives????

Re: m22 how to tell from m21?
 

[ QUOTE ]
[ QUOTE ]
M22 transmissions built late Oct of 1969 had a C designation following the build date. Those transmission built prior did not have that identifier

[/ QUOTE ] Steve, M22s used the C in 1968 date production[69 model year]

[/ QUOTE ]

I meant 1969 production. The identifier was implemented Oct 21st of 1968 for 1969 production. Is that better https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Re: m22 how to tell from m21?
 

[ QUOTE ]
Ct. ???? huh, isn't that where 427King lives????



[/ QUOTE ] Yeah, but he said "real good price" so that eliminates me as the seller https://www.yenko.net/ubbthreads/imag...mlins/grin.gif

Re: m22 how to tell from m21?
 

I was thinking that but couldn't say it!!!!

Re: m22 how to tell from m21?
 

would you one sell for 1200.?(rebuilt)

Re: m22 how to tell from m21?
 

[ QUOTE ]
would you one sell for 1200.?(rebuilt)

[/ QUOTE ] Keep an eye on the parts for sale section, there are some serious deals on some real rare and desirable stuff coming up real soon. You may be amazed.

Re: m22 how to tell from m21?
 

any truth to a drain plug being a idenifier? dennis

Re: m22 how to tell from m21?
 

The begining of the 1970 model year engineering drawing changed to put a fill and drain plug in every main case...
A lot of customer what drain plugs, so I have drilled and tapped many cases to 1/2" NPT, and I know a lot of rebuilder that do the same...
The only positive way of determining if you have and M-22 is to pull the side cover to see if the gears helical angle is 21* (M-22) or 39* (M-20-21)... Hope this helps... Crash

Re: m22 how to tell from m21?
 

[ QUOTE ]
any truth to a drain plug being a idenifier? dennis

[/ QUOTE ]

Sort of. M22 did have the drain plug, however many M20/21's had a drain plug retrofitted for ease of gear lube changes.

Here's a pic of the gear sets showing the teeth angles:

M20/21:
http://i264.photobucket.com/albums/i...DZ/m20-21a.jpg

M22:
http://i264.photobucket.com/albums/ii190/Z28DZ/m22a.jpg

https://www.yenko.net/ubbthreads/imag...mlins/flag.gif

Re: m22 how to tell from m21?
 

...note NO overlap of M22 gear teeth on the same gear while M20/21 teeth overlap the next tooth in sequence..

Re: m22 how to tell from m21?
 

Helical vs straight cut gears... that's what makes it the "rock crusher"

Re: m22 how to tell from m21?
 

lets see if these will attach

Re: m22 how to tell from m21?
 

another

Re: m22 how to tell from m21?
 

last one

Re: m22 how to tell from m21?
 

FINALLY! i really appreciate fellas. thanks https://www.yenko.net/ubbthreads/imag...lins/beers.gif

Re: m22 how to tell from m21?
 

Maybe the mods could pin this thread to help with any muncie question...

Re: m22 how to tell from m21?
 

i'm surprised every car guy doesn't know this. at least I know i'll never forget! thanks guys https://www.yenko.net/ubbthreads/imag...mlins/flag.gif

Re: m22 how to tell from m21?
 

Nice data but the 1970-1974 listing for both the M-20 and M-21 are incorrect the fine spine muncie only appeared in the M-22 for 1970 not as listed it should read 1971 up to 1974 for fine spline input and large out put for both M-21 and 20.

Jim