markxyzbc

Can someone tell me about this transmission?

Thank you,

Mark

joe_padavano

Well, I can tell you that's one too many characters for a VIN derivative, which should only have nine characters.

BackInTheGame

The first four characters seem to be a different font size. Maybe it's just because the photo is out of focus. Maybe a better photo would help.

markxyzbc

Do you suppose somehow it got stamped with the 70 instead of just the 0 at the factory?
I don't see any signs of overstamping or grinding.

BackInTheGame

Things that make you go "hmmm..."

markxyzbc

I used some soapstone to see the numbers better, thoughts?

markxyzbc

Magnified

markxyzbc

markxyzbc

Where can I look up the vin to find out what car it came out of?

joe_padavano

Nowhere. That's not a complete VIN, it's a VIN derivative that only has some of the numbers from the full VIN. And I have to say, "870Z..." has me at a loss. WHERE on the trans is this number located, exactly?

joe_padavano

The VIN derivative stamp on a Muncie should be located here, and note that it only has nine characters.

7314haywood

1970 November 30 M21 gear ratio.. Let's see the cast numbers on tailhousing. It will narrow done some what.

joe_padavano

Actually, K = July, which would be late 1970 model year build. Muncie did not use "F", "G", "I", "J", "L", "N", "O", or "Q" to avoid confusion with "E", "C", "M", and the numbers "0" and "1".





For completeness:

P = Muncie
0 = 1970
K = July
30 = 30th day
B = M21

7314haywood

forgot about missing letters. Corrected the second shift to gear ratio. Had Super T10 in my head.

fleming442

It doesn't matter unless you're trying to verify a numbers matching car, in which case, the VIN derivative matches the dash/cowl. Otherwise, most Muncies are Frankensteined, and it could have a huge mish-mash of parts.

442_1972

I believe the changeover from the 3925660 transmission case (like the one in question) to the 3925661 case occurred sometime in the middle of the 1970 production year. My ‘70 GTO with an April ‘70 build date has a 3925661 case. I wonder if the July 30 date on the transmission case is for an early ‘70 build? As I understand it, the year code refers to the production year of the vehicle, so July 30 might actually be July 30, 1969.