904 issue

Ok. So you said if you shift into D the car will not move but in manual 1 or Low you can drive the car? Did I understand that correctly? If so I would be paying a lot of attention to the one way roller clutch (aka sprag). This is the component which hold the low/reverse drum against rotation enabling 1st gear in D. When you shift into manual 1 or low, the low/reverse band is applied around the drum also to hold against rotation. Which is the reason for movement in 1 & none in D. The low /reverse band is also applied in (as it's name suggests) reverse. If you have no issue in reverse, it means the low/rev band is being applied. If the car will not reverse, the band is not being applied or the band itself is damaged.
My bet is a sprag issue. Just drop the pan & check out what's laying around in there.