M-22 I.D.?

[Bigblockhappy]

I bought a muncie transmission as an M-22 at a swap meet but ain't so sure it really is one.there is a "cc3 code on 1 side and a 5 digit #just below that, the casting #'s are identical between M-21 and M-22 so you can't go by that, the inclination of teeth on gears don't look that straight like it's supposed to be on a M-22. There is no ring grove on input shaft but apparently that no real sign of an M-22.Any info would help.
thanks

[68TopStock]

Does the main case have a lower drain hole tapped into the drain boss?

[Zman]

The cc3 could indicate a replacement case.
The drain plug isn't a sure clue either.
Sounds like the gears are the only way you'll know on this one. With the M-22 gears, you can draw a line between the gears without hitting each other...if you can picture what I mean.
What is the casting number?
Is there a number on the mid plate starting with a "P"
All "661" cases have the drain plug, and even some of the "660" cases. I have a "660" M-21 with a drain plug.
Corse spline, or fine spline input?
Lack of "rings" on the input doesn't necessarily mean anything either... sounds like a worked over box with a replacement case..
What did you pay for it??

[BBIGG BLOCK 396]

Only way to tell for sure is pop off the side cover and look at the cut of the gears,there is a web site on muncie transmissions that will show you the difference in the gears on a M21 and a M22.A lot of M21 trans used the same cases as a M22.There a lot of indications to look for and your trans has all the indications as being a M22! but the only way to know for sure is to look at the gears.

Bobby Dodson