Muncie 4 speed ID info

[LeMans Blue X77]

Can anyone tell me how to identiify these trans?

PO422
PO204
This numbers came from the right side if trans is facing forward. stamped in.

Thanks [img]/ubbthreads/images/graemlins/worship.gif[/img]

[Mr Yenko]

P=Muncie
O=1970
4=April
22=Day

P=Muncie
O=1970
2=February
04=Day
You have seem to have missed the last letter in the code
A,B or C.
The "MOF"

[LeMans Blue X77]

Case is extremely clean and there are no other letters or numbers but the input shaft has no rings cut in them.

[Mr Yenko]

Is the input shaft a fine spline or course spline shaft.
What is the size of the output shaft,Does it have a LARGE counter pin located in the front of the trans or a smaller pin.I compare the rear shaft size to a TH-350 Yoke or TH-400 Yoke.No grove and 1 grove is close ratio and 2 groves would be wide ratio."MOF"

[crash]

These are either 1965 or 1966 model year Muncie's. 1967 and later used a letter code for the month. 1963 1/2 and 1964 had the P-code on the left side. If you could post the main case casting number I could give you the model year... Crash

[LeMans Blue X77]

one one of them it is 3952661 I'll have to get the other one from my buddies shop.

[YENKO DEUCE REGISTRY]

661's aren't '66 or '67's! I think they started in '70 and went through '74 or '75?

Sounds like they might be replacement cases.

[jus4funn68]

If the case is a 661 and the input has no ring on the splines it would have to be an M-22. The spline number does not matter for that year since they made both fine and coarse spline input shafts on rockcrushers. Kevin

[Pantera]

I have worked on a lot of these 4 speeds and have never seen a coarse inpuit spline on a rockcrusher M-22. Are you sure of that statment?

[JoeC]

not all M22 were fine spline
don't go by rings on input shaft to ID a trans
To me, best way is look at input shaft gear.
If it has 26 teeth on 45 deg angle it's M21
If it has 26 teeth on a 20 deg angle it's M22
It it has less then 26 teeth it's M20