I have a 99 C230 kompressor and I can hear this clunking noise when the car goes to a stop or take the foot off the gas and then step on gas a little bit right after. The dealer replaced the modulator, but it is still doing this intermittently. before they replaced it, it clunked when the car went down hillls. The car has 27k miles and what is wrong with the transmission? can it be front flex disc??