I was driving my 2005 BMW 530d when all of a sudden the car made a bang/thud sound and the back tires locked up and I just skidded to a stop. The car wouldn’t move even in drive after that. I put the car into reverse and it seemed to get it self unstuck and it could be driven forward again. After examining the floor I could see pieces under near my drivetrain. Wondering what this is. Left the car overnight and came back the next day. Car starts and drives normally. There is a faint rubbing sound I can hear though, it doesn’t sound good so not testing it to much until I can get a mechanic to take a look. I have some photos and videos of the part that seemed to lodge itself in my drivetrain/differential.

 

STOP driving the car before you do more damage.

That chunk looks like part of the differential.

Get under there and see what has happened. You can see broken stuff in the photo -- the whitish looking lines on the fins.

My guess is someone ran over something or the differential has come loose from some mounting points. If you;ve only broken off a few fins that probably isn't that big of a deal, but moving the car at all risks doing a lot of damage.

 

so I should get the car towed to a mechanic or will that be a problem to because of the wheels obviously having to move to get it on a tow. I’ve had a look under the car and that frame looking thing I took a photo of is the only piece that seems to be broken. One of those pieces lodged itself into the drivetrain initially and that’s what caused the car to be stuck. Putting it in reverse seemed to dislodge that piece.

 

Are you able to get under the car and inspect it?

I guess the first question is how did this happen? And, is more going to happen?

I supposed it is possible someone ran over something and it only broke off some fins and that got lodged like you said and dislodged and now it is all ok.

If it gets towed without inspection first, I'd have them put the rear wheels on dollies while moving it.