My car broke down, and this was under it. Car will start, but won’t drive or reverse, only makes loud cracking noise.
A: The good news is that this is not a piece of the transmission. The bad news is that this is a piece out of one of the CV joints. The ring in the middle.
This means that the axle is broken, and the car won’t drive because the differential is sending all the power to that axle, which is what they do. The crackling is whatever is broken spinning around and hitting things. The good news is that if nothing else is broken, it just means replacing the axle and CV joints, which isn’t nearly as bad as a new transmission.