Muncie Build (Assy) Date Code

[Frank C.]

My Muncie VIN stamp is correct and matches the engine VIN stamp, but the Build Date Code is P01001 - too many numbers. The body build date is B08 - October 8th. This is very close to a 1001 transmission build date. I saw a similar question several years ago concern the extra "0" following the P, but did not find a clear explanation. Any comments would be welcome.

[Dan A.]

Re: Muncie Build (Assy) Date Code

Model year of your car might be relevant.

[Larry M.]

Re: Muncie Build (Assy) Date Code

Frank:

What year car are we dealing with?? If a mid-year, AOS or St Louis body??

Larry

[Frank C.]

Re: Muncie Build (Assy) Date Code

'66 - St. Louis

[Thomas N.]

Re: Muncie Build (Assy) Date Code

Muncie Date codes for 63-66 are as follows:
P, then the next two digits are the month and the last two digits are the Day. There is no year designation in the date code.

Could your date code be 10 01 (October 1) with a leading 0?

67 and 68 codes are as follows:
P, then the last digit of the year, then a letter for the month, then the last two digits are the day.

69-72 the codes are as follows:
P, then the last digit of the year, then a letter for the month, then two digits for the day, followed by another letter for the ratio of the transmission.

It doesn't matter whether it is an AOS or St. Louis body, the transmission dates were stamped at the transmission plant.


Muncie month codes are:

A-January, B-February, C-March, D-April, E-May, H-June, K-July, M-August, P-September, R-October, S-November, T-December

[Frank C.]

Re: Muncie Build (Assy) Date Code

Thomas - I completely agree with your comments. A or S makes no difference. The first digit following the "P" must be a place holder for some reason or an inspector's mark - the following "10 01" fits the car's dated construction sequence.
Thanks for taking the time to offer your thoughts.

[Mike B.]

Re: Muncie Build (Assy) Date Code

Hi Frank,

I think you've figured it out. Sure looks like a stamping error to me. And most probably should've been P1001 without the leading zero. That fits perfectly with your car's build date. Anyway, you've got the VIN stamp on the case so who's gonna argue it's originality?

My transmission is still out of the car so I figured I'd send you a handful of closeup shots to compare to your original. These five shots are from '66 VIN #72XX original M21 Muncie right side. St. Louis final build date December 1st, 1965. Thanks again for your help with that AC bracket. Mike

'66 #72XX M21 Transmission Right Side (1).jpg'66 #72XX M21 Transmission Right Side (2).jpg'66 #72XX M21 Transmission Tailshaft.jpg'66 #72XX M21 Transmission Build Date.jpg'66 #72XX M21 Transmission Main Case Info.jpg

[Larry M.]

Re: Muncie Build (Assy) Date Code

It doesn't matter whether it is an AOS or St. Louis body, the transmission dates were stamped at the transmission plant.

The reason for asking about AOS vs St Louis body early on is that for some model years the letter date shown on the Trim Tag can mean different months: 1966 is one of these years, where "B" can mean either September or October depending on where the body was made.

Larry

[Michael H.]

Re: Muncie Build (Assy) Date Code

Here you go hope this helps.

Mike

http://www.superchevy.com/how-to/transmission/1808-guide-to-muncie-m20-m21-and-m22-four-speed-transmissions/