Muncie Transmission Identification? [Archive] - Team Camaro Tech

: Muncie Transmission Identification?

Mar 30th, 07, 03:53 PM
I have a Muncie tranny and I'm trying to identify which model it is. It has:
3885010 US Patent No 3088336 General Motors Corp
GM 3884883
GM 3846429 on the tailshaft.
Anyone know the model and possibly the gear ratio and what it might fit into? Thank for the help.

Mar 30th, 07, 06:52 PM
Its was made around 1965 - 1967 Thats about all I can tell you with the info provided.

Apr 1st, 07, 12:33 PM
What other information is needed? I know this trannie does not have the fine spline input shaft like most M22's, but I was informed that there were a few M22's that did not come in the fine spline input shaft. I'm trying to find out whether it's an M21 or M22 or another model........thanks for your help.

Apr 1st, 07, 12:59 PM
Take the side cover off & count the number of teeth on the input shaft. Also check the angle of the gear teeth. With this information you will be able to tell if you have an M20, M21 or M22 gearset.

Apr 1st, 07, 01:01 PM
All muncies before a certain year (1970 I think) had 10 spline input shafts, m22's included. '70 and later all were 26 spline.

Ones older than a certain year ('68 I think) used nuts to secure the shift arms to threaded shafts sticking out of the side cover. Later years used bolts.
The length of the flat that engages the shift arm is longer on the "bolt on" types. You can use a "bolt on lever" on a "Nut" trans, but not the other way around.

"camaro" transmissions have the speedo drive on the passenger side. All others have it on the drivers side.

It's worth noting that the passenger side speedo drive was to clear the 67-68 crossmember mounted muncie shifter. If you're using an aftermarket hurst shifter and converting a former automatic car, a driver side speedo muncie is a boltin, and your existing speedo cable will screw right in.

All muncies used the same bellhousing bolt pattern and bolt size, the length, and the same transmission mount.

A muncie and it's bellhousing are the same length as either a powerglide or a T350, and will directly bolt in.

Many but not all muncies were "coded" (M20, M21, M22) by grooves cut into the input shaft, none, 1, or 2, though which is which escapes me.

Apr 1st, 07, 02:58 PM

You getting too old!!

He, He!!

Memory failing you indeed..

Seem's ta me you remember a WHOLE bunch about them..

Great run-down, now hurry up and remember about the grooves!!!

He, He!!

You missed a good afternoon w/ myself, Travis and Mark B down at Woody's Pub&Grill yesterday. I inadvertently called Mark, Jim b/c I was thinking about how nice it woulda been if you coulda been w/ us, but 5 hours away is a tad much of a short road trip just ta jaw for 4 or so hours w/ us old gearheads!! Maybe next get together??


Apr 1st, 07, 03:19 PM
Here is a good site for correct information on Muncies.

Apr 8th, 07, 12:11 PM
I found some more numbers on the Muncie if that helps.....
GM 14
and the other numbers stated above:
US Patent No 3088336 General Motors Corp
GM 3884883
GM 3846429 on the tailshaft
I hope this might help me identify this Muncie. Thanks again for all your input.

Apr 8th, 07, 05:12 PM
Nah bro,

They are just castings and might even be thrown together in a shop.

You main case was made from 1965 - 1967.

Take a look on the side of the case you will see a derivative of the vin and a date broadcastin no. It will be something like p8b14 which is mine but mine has a b at the end.
The early ones till late 66 I believe.... eg P0412
They changed to something like.... P6B10 in 67 to Oct 68. The B was the month of February so C would be March

From Late 67 to 74 they added an extra letter at the end...p8b14B. That last letter easily tells you the ratio. A...M20, B... M21... C...M22. This made it very easy

There are a lot of other things to take into consideration as it is a process of elimination on the earlier ones.

There is a thread in Nasty z28 somewhere that kicks this in the ***.

I have the ultimate contradiction. I have a date code of... p8B14B
P - Muncie, 9 - 68, B - Feb, 14 - the day of the month B - M21 Which is od because they didnt start using the end letter untill Oct. of 68, so it may have been stamped later for some reason.

Apr 8th, 07, 05:15 PM

Apr 11th, 07, 10:05 AM
What would an M-21 Muncie tranmission be worth that has been rebuilt but never installed in a vehicle? Thank you for your help.

Nov 2nd, 07, 08:28 AM