Manual for automatic drive expansion

Hi guys. Since my gearbox is leaking at my 2.5, I want to do it with a workmate on a stage. He knows about AG, but we want to see if there are any special features. Is there a manual for automatic transmissions here? Do you have to pay attention to something? Maybe someone has a link. I couldn’t find anything right now. I have to go to TÜV this month:-( . Thank you in advance.