T85 casting date

[JimNolan]

Guys,
    I've decided to rebuild my T85 transmission and would like to know what year it was made. The Passenger side of the transmission reads T85C-1A and the number inbedded in the drivers side vertically is  A2452.  The vertical number is in the same place as a 70's model T10 casting date, so I'm assuming its a casting date. The overdrive section is R11=1E. I hope someone knows what year this was made, I can't find anything on the internet either.
THANK YOU,
Jim Nolan