727 Disassembly and Advice

There are basically 3 books to have. 1 was already mentioned, the other is this, not the link to buy but the book title/ author..., Munroe

https://www.penguinrandomhouse.com/...=PRHB7BD76FBDB&aid=14813&linkid=PRHB7BD76FBDB
and then an OEM service manual for the transmission you are using. That part is easy, go to MyMopar and download the appropriate service manual, free:

You may need to get Dodge vs Plymouth, depending on year

https://mymopar.com/service-manuals/