dmytro100

Hello all, hoping to get some insight.

I have a 2017 E300 with almost 70K miles on it, lately I have noticed a whining noise that only occurs while coasting, noise goes away on acceleration or braking, and persists in neutral.
The rotors and brake pads are new (<500 miles on them) so I don't think its bent rotors.

Not sure if I should be looking at wheel bearings, torque converter, or front differential.

Any help is greatly appreciated.

W205C43PFL

Does it whine at a certain speed as well, at different ambient temperatures? Does the noise get louder at specific throttle input and speed?

The G Man

What you are describing sure sounds like a noisy wheel bearing.

dmytro100

Thank you for the response,
The noise can be heard throughthroughout, but is most noticeable when coasting between 30-40mph, it is louder when the car is warmer. The noise goes away as soon as there is throttle input and the car accelerates.

W205C43PFL

You are welcome.

I see, yup good advice from the previous post on checking the wheel bearing otherwise also check the rear differential as well, hopefully it is the former that you have to deal with. What I mean by rear differential would be something like this: https://mbworld.org/forums/c450-c43-...-thoughts.html

I would also suggest tires although it doesn't sound like tires could cause what you are dealing with I did read posts on this being the cause for some reason, it is possible that the load on bad tires is causing some sort of mild stress on the components (?) I don't know that is what I heard.

The G Man

70,000 miles is a bit premature for wheel bearing failure. Factors that might accelerate wheel bearing failures are aggressive driving, low profile tires, tires out of balance or suspension or alignment issues.

W205C43PFL

OP's problem could very well be just tires then hopefully.

dmytro100

Hello all,
It was the rear differential, similar to the C43 thread. Thank you again for all the comments, hopefully this helps other diagnose.

W205C43PFL

Thanks for your update @dmytro100 , what was the fix? They replaced it?

dmytro100

Yes, the rear diff was replaced with a new rear diff assembly.

W205C43PFL

I see, do you mind posting the work order and/or part number? Thanks!