Hello,
I have a 2003 ML350 with only 130K.
However, just yesterday, as I am driving I heard this ticking noise coming from the rear. As soon as I accelerate it starts and gets faster and faster until its like a motor clicking fast. As I decelerate, I hear it going slower and slower until I stop. It stops totally when the car is not moving. I start moving and it starts again. Its really annoying. It doesnt sound like coming from under the car. My guess is the Wiper motor but I am not sure.
Please if anyone can help, let me know.

Thanks from Toronto.

 

I just found out the sound is coming from the right rear wheel.
Sounds like a wire is touching the wheel every time it spins. My rotor and brakes are good.
Thanks

 

Your rotor and brakes might be good, but you should remove the rotor and see if anything on the parking brakes shoes has become undone.

 

Thanks, I will be taking it to my local mechanic tomorrow as it is too cold to work outside. Will let you know the result.