Got a very slight knock from my rear end when I change gear, it happens when I go from 1st to 2nd then bring the clutch up I hear it. All other gears are fine. Makes me believe it's maybe a bush etc ? My haldex Has been done, but it won't be that as it's only a slow jerky speeds I hear it. Once I'm up in 3rd etc the car stays smooth between changes. Any ideas on what this could be?