if it's an M21 or M22? At first the guy I bought it from said it was an M21, then he said M22, then M21. Where can I look to find out?

Elliot

 

Only way to know for sure is to pop the side cover and check the gears. M20 and M21 gears have teeth at an angle. That's so they make less noise. But the angle pushes one gear of the meshing pair forward, the other backward. M22's have straight cut gears because noise wasn't important, strenght was. Gears are also about 1/4" wider than 20/21's.

 

I know you can tell by how many rings(grooves) there are around the input shaft. Some have one-m20? and m21 has two or something like that. I'm sure someone more knowledgable will chime in and verify this.

 

Sorry Zed, only way to tell for sure is to pull cover.

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


This site can help you! Good luck, and let me know if you have any other M22 questions.
Guido

 

Actually the M-20 has two rings, the M-21 has one ring and the M-22 has none along with the 1963-65 M-20.

Take a look at this:

http://www.camaros.org/trans.shtml#MuncieRatios