Trans ID and Date

[ManicGMC]

I have a 63 gmc and after some initial research it appears that when the small block chevy was swapped in they also swapped in an sm465 and maybe a different rear end.

For the transmission, see the attached pic. Want to confirm this is an sm465 and would like to figure out how to nail down the manufacture date.

Stamp ID:
465452
9312

I believe the 465452 points to a sm465. The date code 9312 might refer to 9 month but then 31 wouldnt be the day of the month because september doesnt have 31 days. Finally the 2 might be 72? 82? Thanks for any help.

[FetchMeAPepsi]

if reverse is left and down, it's a 420. If it's right and down, it's 465.

[ManicGMC]

Yeah it's right and down, was one of the things that clued me in to it not being a 420 once I started researching it and realizing it wasn't just the engine that had been swapped.

Was hoping to get some info on decoding the stamp on a 465, I have yet to find those specifics when searching on the web.

[Ed Snyder]

if reverse is left and down, it's a 420. If it's right and down, it's 465.

The original 435 in my '67 pickup is also right and down for reverse.

[Funky61]

From what I found the casting numbers on case are GM 465452, 6273212 or 3901127 to indicate the SM465.
Also top shift cover should read GM390113.

From a Muncie transmission website I found I interpreted the 9312 as;
9=1969, 3-3rd month MARCH, 12 is 12th day


Just my read on those 4 numbers and how other transmissions were broken down on that website. There is nothing specific on the 465 there.

https://www.dmetransmissions.com/casecodes