the 727 and 904 are the easiest transmissions there are to rebuild. if i can do it, anyone can. [well, almost anyone. biggrin]
the hardest part is the disassembly and reassembly of the valvebody, [just pay attention] and if a guy can do that, the rest is cake.
as said, get the monroe book. and for extra help, get an ATSG [Automatic Transmission Service Group] manual, available many places for $20-40.00.
beer