Question Details

I have a 2013 Meecedes C300 AWD. Recently I've been hearing a roaring from the rear of the car when im at slow speeds turning either direction. Once i straighten out the noise stops completely. The shop suggested that i replace the front, rear differential fluids as well as the transfer case. Which we did 350$ later and its still making the same noise. Any advise on what it might be?


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MercedesMedic  1 year 1 month ago

It is most likely the rear differential going bad or a wheel bearing. Something else to consider is the Giubo joint, also known as the flex disc.

Can you try to take a turn but put the car in neutral before you turn?

If it doesn't make the noise with the transmission in neutral, my guess would be its the wheel bearing.

Be careful and do this in safe area such as an empty parking lot. Stop before you put the car back in gear.

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Tygers1988  1 year 1 month ago

The dealer originally requested i have my 4wd fluids changed. Front rear and transfer case which i did. They claim to still hear the noise and think its the transmission.. very expensive to "think" thats what it is. They originally couldnt even hear my original noise. I have heard i should drive it a few 100 miles with the fluid changes and it could go away. But with no slippage and just a light growling when turning i have a hunch i dont need a new transmission. I will try the turning in neutral though tomorrow sometime.