m22 how to tell from m21?

[vettem]

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

[427king]

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.

[vettem]

what should the gear angle be? thanks

[427king]

Added that above as you were responding..

[wheelhop]

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

[Steve Shauger]

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.

[427king]

[ 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.

[427king]

[ 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]

[vettem]

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

[wheelhop]

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