I guess all my cars were built farther into a production year so this has never come up before. My friends car is a Jan 69 car and the date on the trans is P9T10A . Muncie , 69, Dec, 10th , M20. So the second digit is for the year of the car the trans goes into not the year the trans was built? Am I correct? This just seems strange to me, What did they do with the transmissions left over after they ended production of that model year. Everything else on the car the date codes are the dates part is built. Enlighten me please .Gary

The truly educated never graduate

Ref: http://www.chevellestuff.com/generic/muncie.htm

The serial number is a date code and indicates the particular year the transmission was built for. Serial numbers from 1963 to 1966 included only the month and day. P0101 indicates January (first 01) 1st (second 01). In 1967 and 1968, the serial number got a year designator and a letter designator for the month such as P8A01, meaning 1968 (8), January (A) 1st (01). Note that a Muncie dated with a December build date it was actually built the prior year. An example would be the date code P8T13, meaning 1968 (8), December (T), 13th. The transmission was assembled December 13, 1967 for the 1968 model year. The 1969 to 1974 Muncie got a ratio designating letter at the end of the serial number. An example would be P2R25B. This decodes to 1972 (2), October (R), 25th, M21 (B).
Date Codes: A ~ January, B ~ February, C ~ March, D ~ April, E ~ May, H ~ June
K ~ July, M ~ August, P ~ September, R ~ October, S ~ November, T ~ December
Type Codes: A ~ M20, B ~ M21, C ~ M22

TH400s are dated the same way. A TH400 for a 1969 model year car is dated from January 1, 1968. A date code of 69CE290 is 1969 model year, CE (396/350hp) and 290th day counting from Jan 1, 1968 or October 17th meaning it's for a 1969 model.

Why? That's just how they did it. :)

Ref: http://www.chevellestuff.com/generic/muncie.htm

The serial number is a date code and indicates the particular year the transmission was built for. Serial numbers from 1963 to 1966 included only the month and day. P0101 indicates January (first 01) 1st (second 01). In 1967 and 1968, the serial number got a year designator and a letter designator for the month such as P8A01, meaning 1968 (8), January (A) 1st (01). Note that a Muncie dated with a December build date it was actually built the prior year. An example would be the date code P8T13, meaning 1968 (8), December (T), 13th. The transmission was assembled December 13, 1967 for the 1968 model year. The 1969 to 1974 Muncie got a ratio designating letter at the end of the serial number. An example would be P2R25B. This decodes to 1972 (2), October (R), 25th, M21 (B).
Date Codes: A ~ January, B ~ February, C ~ March, D ~ April, E ~ May, H ~ June
K ~ July, M ~ August, P ~ September, R ~ October, S ~ November, T ~ December
Type Codes: A ~ M20, B ~ M21, C ~ M22

TH400s are dated the same way. A TH400 for a 1969 model year car is dated from January 1, 1968. A date code of 69CE290 is 1969 model year, CE (396/350hp) and 290th day counting from Jan 1, 1968 or October 17th meaning it's for a 1969 model.

Why? That's just how they did it. :)

Very good explination!!!
You can also look here to see aditional info on Muncies http://www.5speeds.com/muncie2.htm
K

Thanks Guys. I do understand the translation. I actually searched all posts and links on this site before I posted. It just seemed odd to do it this way. Maybe the left over ones went to parts. When something seems odd I always question it. Some of you who restore and judge must have vetted this translation of the stamping or it would have come up before now. Sometimes someone starts a belief and before you know its considered truth. Case in point. 1969 Z28 crossrams. It was thought for over 20 years that they came in the trunk and were dealer installed. Jerry M in his book proves this wrong. His research found no RPO or special order #s for the crossram in GM sales dept. records. No # means they could not have ordered it. Just a myth. Dealer installed ,ordered through parts. Gary

The truly educated never graduate