[F10-535]

First time posting. I recently replaced my engine (2015 535 n55 x-drive). Recently as in 7 months ago or so. Bought a rebuilt engine installed my self. After a month I noticed a tapping/knocking noise was very very subtle but I could only hear it at idle I checked under the car and found nothing. Fast forward to a week ago driving the car it sounds like a pulley or bearing was going bad and that noise got a lot louder. Yesterday just driving the car started to sound like it was knocking very loud but I could tell it wasn’t a normal engine knock sounded more from the torque converter fly wheel area. Inspecting the torque converter I found that it was loose it had free play where I could go left right in out as if it was loose. Torque converter bolts were tight. I removed tc bolts and checked fly wheel. It was loose. I figured the bolts might have backed out. So I dropped the tranny this morning only to find the bolts are nice and tight but where the flywheel goes it had alot of free play. Kind of stumped what am I dealing with here. Engine ran fine no issues no check engine light. I haven’t even put 15k miles on this new engine. Is the crank shaft bad?

[F10-535]

https://youtu.be/-zdsNpMMUFM