Scraping sound from transmission
 

I have a 2001 X5 E53 and just replaced the motor. Once everything was hooked up and started it up, I get a loud chirping/scraping sound coming from the front of the tranny. I have replaced the oil/filter, and once filled the noise continued. It sounds like a metal on metal scraping so my first guess was the torque converter and someone suggested it was the flex plate, but the flywheel/spacer/flex plate all went on fine and didn't appear to be warped. The flex plate also attached to the torque converter fine and transmission/engine came together smoothly. I attached link to the clip showing the issue: https://photos.app.goo.gl/8opAnD51VH5JhaeC9

There are only a few things it could be in that area - starter, flex plate, flex plate to crank bolts, torque converter, torque converter to flex plate bolts, transmission pump assembly. You don't mention if its a 6 or 8 cylinder...

Based on the sound, I would check the torque converter bolts.

It is a 3.0L 6 cylinder