My friend just got a 2002 ML320 with 50,000 miles. He just noticed a strange noise coming from the rear while driving. You can really hear it when driving at about 45 mph. woooooooooooom. Especially on the highway and when pressing on the accelerator. Any help would be appreciated. He got a car from a Mercedes dealership, and the car was suppose to be certified pre-owned.

 

not a tire noise?

 

It may be a tire noise, but I told him to take the car back and have them check it out anyway. What else can it be though?

 

He took the car back to the dealership, and they kept it for a day. When he picked up the car, they told him that they've changed the fluid for differential and the noise was gone. WRONG, the noise is still there and it's definitely not a tire noise. The noise is heard when going around 45 mph, take the foot off the accelerator, it goes away, press the accelerator again and it comes back. Any thoughts?

 

it must be coming from the drive train.

 

Any idea what can it be? Mercedes technicians seem to know nothing about mercedes.

 

does it comes on with the differential lock "on"?

ask your friend to try with and without lock.

compare and see if it doesn't go away.

too difficult without hearing it actually.

in noises, the mechanic doesn't have to be an MB experienced to detect them.

 

What do you mean with differential lock, ON??? I'm really sorry about asking a lot of question, I am
trying to help the guy. It's his first mercedes and he paid a lot of money for it. Differential Lock On?? Thanks for your help.

 

Can it be a CENTER DRIVESHAFT BEARING.

 

possible too.

but it does more vibration than hum.