I've recently noticed a knocking sound coming from the back of my car which seems to occur as I am coming to a halt or taking off again from being stationary. It is especially noticeable if I think I am stopping and then I don't have to, like slowing down at a roundabout. My Haldex oil has been changed on schedule and I've checked in around the spare wheel well for anything loose, but nothing. Anyone else have this with their cars? Thanks.