I am going out on a limb here to try to explain what is happening, bare with me.
I have a 2004 318i BMW with sports pack.
Yesterday a strange noise started, it's kind of a metal clicking / clanking noise which sounds like it's coming from the rear. I hear it almost constantly and it varies in loudness and in tempo. On lower speeds, it is louder when I gear down with a lower tempo, then it disappears for a while. On higher speeds it is not as loud but with a faster tempo. The sounds is not constant but almost.
I had this a couple of months ago but it disappeared after I fitted four new tires and asked them what it could be, they jacked/lifted up the car and said I should start the car, put it in gear and give a little gas. The left rear wheel made a weird shuttering/rattling noise. The guy told me that it might be a pin inside my rear CV that's loos/undone. After this the noise stopped and returned...yesterday.
I know it is hard to help someone based on explanation and sounds, but if anyone knows what it might be, please let me know, it would be much appreciated. (give opinion first without reading second paragraph and if different with reading second paragraph)