I was fixing the upper control arm and had the driver side axle shaft inadvertently separate at the center joint (didn’t know it did that). I had to remove the axle shaft to get it back together however the axle nut was still on. long story short, when I put it back in it did not seat (because the nut was still on) and popped out after a mile from my house. We towed it back but did not realize the end of the shaft was grinding against the transmission hub (where the shaft inserts). It wore the tip of the shaft from the c ring to the end way down. I didn’t realize this and when I got back I took the axle nut off and seated the shaft. After about two days it popped out about an inch and began leaking. I pulled the shaft and replaced it with a new one and now the car run fine and shifts fine but when in park or netural I can hear a slight rasping noise coming from the tranny where that shaft inserts.

what did I mess up?

 

Can't tell you without seeing it. Pay attention and if the noise gets worse/louder, pull the trans and split it.