Whining noise 08 C300 4Matic Speed dependable
 

Hi guys,

I've been noticing a whining noise and its getting louder everyday.

Today I decided to put my 4matic car on top of 4 jack stands, dyno moded, turned on and drive it to 60mph. While my wife was inside the car pressing the accelerator, I went ahead and listen to each wheel, I thought it might be a wheel bearing issue, but no...

The noise is coming directly from the gearbox area.

This whining noise depends only on the speed. I tested today driving up to 80mph over the jack stands, put the car in neutral and turning it off and the noise would still be there.

What do you think this could be?
Thanks in advance

Check your alternator, I've had it start doing that on another vehicle. Took it in and sure enough it was that and got it replaced and the noise went away. Same scenario, very loud whining sound that changes with speed.

Ah missed the info about the gearbox area...

Good luck

Thanks folk...

The thing here is that if I turned the car off and left it in neutral, the noise would still be there. The alternator is already stopped in this scenario.

There are other posts regarding transmission problems. I think one has a link to a video of someone who recorded the sound of their failing transmission. It might be worth finding it and see if it sounds familiar. I hope it's something else. Good luck....

your transfer case is goin. hope yoiu have about 8k to blow

Sorry to hear about your transmission woes...

Does anyone know if this was a problem through all the years or only 2008?

Are there any steps one can take to prevent this problem?

Most likely did not service transmission around 39k miles. That is the best way to ensure longer life.

Gotcha. I wasn't sure if I should avoid the 2008 because of transmission issues...but the problems seem to be pretty few & far between...

...as long as the MB mechanics aren't getting lazy & not draining the TC. I just read 7 pages of this thread:

https://mbworld.org/forums/showthread.php?p=5473916#post5473916

unfortunately US dealerships , most, not all, refuse to drain the TC . As in my case the car is already having rough/slippage on gear changes when slowing down. They refused to drain the TC and the problem persists but yet they state it could be something else, so taking it in Friday , good thing its under CPO. This time around they are going to do everything under CPO before I allow them to charge me a dime. Hope no one has to go through what I am.


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Hi again guys...
I took the car today to the dealer and they diagnostic that the transfer case is bad, they said I have to replace the entire transmission. 6500$... Which I'm not doing at all.

DO you guys think I can repair this? Did anyone repair this already? Is this transfer case replaceable without having to replace the complete transmission?

you are pretty much stuck paying that..........

theres no aftermarket option, you must replace the whole trans as well. 6500 is on the cheaper side from what i have seen. this is kinda frequesnt with these cars, noone has done a fix themselves. your stuck paying the 6500

I called a guy who owns a transmission shop in Orlando, he specializes in Mercedes Benz and he said I can purchase just the transfer case, a used one and it can be replaced.

i would stay away from that guy then lol

these transmissions are not like the w203, they do not have seperate transfer cases and transmissions, the transmissions have the transfer cases built into them and are all once piece which is why they are so expensive.........

tell that mercedes specialist he needs to go back to mercedes training lol

Yes youre right...

What If I get a used one at carpart? How is it going to be with the computer?

Blast from the past...I realize this thread dates back to 2012. Curious what OP ended up doing. Thanks for posting as I wasn't sure if my symptoms were TC or something else.
I have 2010 GLK 4matic with 105k miles that I have had since new. It developed very similar noise :more of a whine, speed dependent in both D and N and doesn't depend on the load. The noise becomes faint and can be muted with radio playing.
Inside of the car the noise was coming around where center tunnel and center console connect. I was hoping this was front diff issue.
I did similar diagnostic of putting car up on jack stands and running to 60mph and the most pronounced noise was coming from back of the transmission. It is a bit hard to pin point the noise among all other noise that engine and valve-train creates.
When you read workshop it says the grinding noise that is load dependent and indicates pitted bearing and the whole transmission should be replaced. However, there are materials on replacing TC only.
The 4 bearing that are known to fail due to insufficient lubrication are 150bucks along with two seals. So I'm hoping that I'm catching the issue early and going to give a shot at replacing the four bearings in the transfer case. There is really no downside to trying at this point.
I will post progress here:
https://mbworld.org/forums/glk-class...anny-diff.html