Need help! weird sounds from axels.

[StalinDrift123]

So, i have a problem. When i put car in reverse and try to back up it makes this weird rattling sound and it feels like its coming from the back brakes or axels. its a bit loud and happens randomly and not too often. the brakes were replaced not too long ago. :(

anyone had the same problem by any chance?? anyone knows how to fix it and whats making the sound??

Thanks lot.