Okay so when i reverse in my car and brake to come to a stop i hear a wierd sloshing noise. It is really faint, but i can still hear it, this only happens in reverse. None of this sound when i go forward and brake to a stop. Can anyone tell me what wrong with my car?

Boost fluid.
j/k
Probably gas in the tank, does it do it on a full tank?

haven't tried cuz i just noticed it, but why wouldn't it make that noise going forward coming to a stop.