The 904 and 727 are great transmissions to learn on. Buy the rebuild book on Amazon and there are some videos on YouTube as well. I did my first and so far only transmission rebuild last winter on my 727. It does leak but that’s 100% on me for not using new crush washers on the front pump. The kit came with them but I skimmed past the part about the washers being single use and my old ones “looked good” to me.
