what transmission is this?

[mrnielsen]

I have a manual gear box with some nice cooling fins on the bottom. real oem couldn't locate this with the numbers cast into the side. I have not called bmw (they are closed now) and am not sure where else to go with it.
So the help will be appreciated!

It fits the m30 motors from e28 533i and same era 733i

very small is 0012500E
and then what im used to seeing 260.0.1302.90

is this just a fancy case 260? if so which series did it come out of. If not what is it and where did it come from?

Here are the numbers

Here is the box

[MR 325]

This is definitely a trans for a M30 car. It's a 260/6.