Dealer replacement M22 codes

[bitfactr]

I purchased a '70 LS6 Chevelle from the original owner
a number of years ago. The M22 in the car at the time was
said to be a dealer replacement done in '72 after the
original was damaged (luckily the original trans was kept
and since repaired). But I'm trying to decipher the codes
on the other/dealer trans.

The straight-forward numbers are the casting number
(3925661) with stamp (WJ), with date code P2K06C: Muncie,
1972, July, the 6th, M22 ratio.

It doesn't have a sequence number, but to the left of
the date code is OT3 with 40201 below that. There is also
an "A" stamped on the top and a 5 cast into the side of
the case near the date code? I can provide photos if it
would help. Anyone have any info on these codes?

Thanks,
Dennis