Muncie ID 21 or 22

I picked up a muncie today for the 50 F1 project. Was hoping that someone might be able to ID it for me by the serial numbers or tell me what to look for to ID it. Numbers on the outside are 3925660 and 3857584GM. Lots of thanx in advance you fellas never let me down.

Fugee

 

Here you go

http://www.geocities.com/MotorCity/Factory/4633/Pictures/muncie.html

 

the info you seek is at http://www.gearzone.net/muncie2.htm
I run a muncie m 20 close ratio in my 56 pontiac ,their great 4 speeds ,good luck!

 

hanx guys that lets me know its a 68-70 but is there anyway to tell ratios from the outside?

 

Nope, gotta count teeth....unless.....maybe you could count rotations. Just pop off the inspection plate, nothing to it. Close ratio ******`s have more pitch on the gears if I remember right. Havent messed with a Muncie since the late 80s...cant afford em anymore!

 

go to www.4speeds.com/muncie2.htm. Good info. casting # 3925660 indicates year 1968-1970. There is a serial # on the case rt side back edge next to the extension housing, turn trans to where tailshaft is @ 12 oclock, input shaft 6 oclock, will give you serial #, more info available from that. Surefire way tell gear ratio is pull side cover count input shaft/cluster gear teeth. Also then you know what kinda shape it is in. M22 has 20 degree helix angle on gears, M21 has 45 degree. Easy to spot M22 gears look almost straight compared to M20 & M21. If its an M22 and good shape worth a bunch of money

 

Doesnt the M-22 have an extra fluid drain hole on it also??

 

no. All of the 3925660 cases have the drain plug. Pull the side cover, angle of teeth on gears only surefire way to tell.

Tiny, let us know what you find out.

 

Can't gear ratios also be identified by the # of grooves on the input shaft?

 

Check the in put shaft,I think the close ratio has a groove in it and the wide dosen't--TV