Does anyone know how to de-code a muncie transmission?
I have a trans and am trying to determine what it is out of.
The case # is 3851325, the tail housing is #3846429 and there is a small marking next to the side cover P03(3)09. Any info you might have would be great. Thanks

I believe you have a '64 trans with a 7/8" counter shaft. Should either be a M20 or M21.. If there is one ring on the input shaft its a M21, close ratio. If no ring its a M20, wide ratio.. P0309, thats the date - March 9th.. I dont know how you can tell what it came out of originally..

A lot of the old Muncie's have been rebuilt so many times, it's hard to tell what it came out of originally. Like Jason said, it's either a M-20 or 21. You should also have a VIN stamping on your transmission which would get you closer to what you have. It would be on either the top or side of the main case close to where the case mounts to the tail shaft. The VIN stamp varies between years and which plant it was built in. The VIN should be close to the date stamp (P0309). Let us know if you find it.

Great Thanks. I will look for the vin stamp. I will post when I find it.

I believe the vin # is L137440? Does this sound correct?
Thanks for everyones help in this matter.

How do you tell the # of rings on the input shaft?

The Ring Is Really A Groove Cut @ The Diameter Of The Input. Just Plain Splines Makes An M-20