When driving at highway speeds and sometimes applying the break, I get a tapping/banging/knocking noise on the underside of the driver's side. This does not happen when travelling locally. I have had the car in twice to the dealer. First time they said they could'nt find anything. Second time, they replaced the bushings. Said they didn't know if that would fix the problem (it didn't) , still couldn't find anything significant wrong with it. The noise is very loud at times and sounds like something is going to break. The car is a 2000 dodge caravan se. Does anyone know what it could be? Thanks.