hotwiredbenz

My 03 E500 has been making some strange noises at high way speeds. If I take the car up to 100 really quickly and then start slowing down gradually, I hear this noise coming from the drivers side rear. It sounds a bit like a piston slapping noise, but obviously its from the back so its something else. Its hard to describe exactly...its sort of like a jackhammer noise but much softer. Most people in my car dont notice it unless I tell them to listen for it. It gets faster and higher pitched as I go faster. Once the sound starts, it continues prety much the entire drive until I get down to speeds below 40. It goes away somtimes randomly.

The sound is completely dependant on the car speed and not engine speed. Switching gears and putting the car into neutral has not effect on the sound.

Ive also noticed that the noise will start right away if I enter a highway pretty fast on a ramp that turns right (meaning the weight of the car is on the left). The sound will then almost instantly start up. Furthermore, Ive also noticed taht the sound switches sides when cornering...its typically on the drivers side, however if I corner on a left curve, the sound will switch to the right side momentarily (and then return to the left once back on straight road)

I took the car to the dealer and they replaced the entire rear differential..yet no luck. Any suggestions on what I could try next? I thought it might be the tires, but I had all 4 replaced and rotated and it still comes only from the rear. It does not sound like road noise but rather something mechanical. i also notice a slight vibration in the wheel & gas pedal.

Any help would be apprecaited...this problem is really bugging me.

sprink49

Years ago I had the same symptoms with a 735 BMW. I eventuallly replaced the drive shaft and universal joints and the noise went away. I would take it back to the dealer and raise hell. I heard there were quite afew buy backs on E class cars that could not be repaired.