1965 904A modification.

The book from Tom Hand is good, but be aware that he is mostly describing a later model 904. I rebuilt my 69 904 and always used the specs out of the 69 shop manual. I suggest to use the book from Tom H. as a general manual for dissembling, testing and assembling, but when it comes to washer thickness, number of clutches and other specs, refer to the original shop manual. W.I.T. for example has a lot of parts for pre 70 904 transmissions, but you need to search with the part number.
Happy wrenching,
Wolfgang