What year/spec 727?

Where can I find out what the numbers on transmission tell me? Is there a web page about these? Or anyone with a book of info?

Numbers cast on top of trans: 844-4
punched on rear left side: 3410 844-4
On pan rail, left side: PK3410767 (maybe PK34107671) 2996 5055
On passenger side OA156366

Thanks.