There is or was a great mechanic on Youtube who went through a 1947 or 1948 and detailed everything he did to it. One item was taking the transmission completely apart and reinstalling it's parts. He posted great videos and talked about what he was doing in detail. Unfortunately I can't remember his website. He was in the mid-west somewhere.
Maybe someone on the Chat will help identify his site for you. I think he lived in Nebraska and used the states motto (Cornhusker, maybe a part of his site ID. Not sure about that.
Also, I think the service manual covers taking the transmission apart and reassembly,
Good luck with it.
Best,
Charlie
