Pete7874

As of late, our C300 has started to emit this metallic whine sound that becomes more high pitched as the car's speed increases. It seems to be coming from the right front. I initially thought it may have been the tires, but the sound is kind of metallic in nature. Is it possible it's a wheel bearing? I thought wheel bearings mostly make noise when you turn and not when going straight, but maybe I'm wrong about this? How would I check for a failed wheel bearing? Are wheel bearing failures common on the C204?

60K miles at the moment.

Thanks!

Pete7874

Another possibility: front differential.

spyked

Based on what I've read....well....let's just say I hope my gut feeling is wrong (if you are out of warranty).

Let us know what dealer/mechanic says.

Pete7874

What is your gut feeling?

Carsy

Possibly a stone caught between stone guard & disc. It has happened to me 3 times now.

spyked

Too many 4MATIC failures (transfer case) requiring ENTIRE transmission replacement since transfer case is PART of the transmission in these W204/X204 cars. Front end whine and noise is the first symptom.

Keep us posted.

Pete7874

Thanks. Taking the car to the dealer tomorrow.

If it is in fact the transfer case, how much longer do you think I can drive it like this before it conks out on me? I've got a 200-mile trip to do this Sunday, so this is concerning.

spyked

Wish I knew. I haven't heard of any "stranded on the side of the road" type of failures of any type on these cars (aside from EIS issues obviously).

As you said, could be a bearing or differential issue too. Or a brake issue.

Let us know what dealer says on Monday, and good luck

mstrbenztech

If you can pinpoint this to the r/f then yes you are looking at a wheel bearing issue. This is pretty common and all of these bearings are sealed units that have to be pressed into the knuckle. You cannot diagnose without putting it on a lift. You have to put in dyno mode and hold the suspected wheel and have someone slowly accelerate. You do this for all wheels you are checking, if the noise comes goes away when you hold a wheel, then there is your bearing issue. The transfer case whine you usually hear more in the center console area. Like stated above, front diff is also suspect but I have only replaced 2 of these for whining in these vehicles. Sounds like transfer case or bearing. I would say you will be ok and not get stranded. You would have to put on some serious miles with this whine for it to actually break. The whine in the case comes from the bearing that the front driveshaft attaches to.

Pete7874

Wife just called from the dealer: apparently the car needs a new transmission.

rshah31

Bummer! Are you under warranty? Keep us posted on how the repair process goes.

Recently, I was perusing CPO C300 4matic models at my local dealer and in the CarFax history report I noted that three of them had transfer cases completely replaced at under 30k miles.

Is this a common weak point for 4matic cars?

spyked

I was afraid of that Pete.

I personally don't understand how Mercedes Benz, the oldest car company in the world, could have under-designed such an integral part of a car. I'm even more disappointed that they haven't recalled the faulty units.

Hopefully they give you some goodwill relief.

Pete7874

Luckily the car is still under the extended MB warranty. This warranty has paid for itself many times over by now. Still disappointing. Wife was considering another MB in the future, but based on all the problems we've had with this one, I don't think she'll give them another chance.

Glyn M Ruck

Another 4Matic transmission failure. It's like a rash at the moment.

Was the transmission serviced at 39K miles?

Pete7874

Yup. Of course it was serviced the American way, which means "half serviced."

Glyn M Ruck

I find it interesting that these failures only seem prevalent since they integrated the transfer case with the transmission.

spyked

EXACTLY. It affects the W204 and X204. How do we know what MB models use the 7G Tronic WITH 4MATIC but NOT an integrated Transfer Case.

For example, would W211 and W212 E Class 4MATIC cars be safe? Are the Transfer Cases separate? What about ML models?

Glyn M Ruck

The W211 did not have an integrated transfer case & never gave trouble. I would have to check the others.

Pete7874

On a related note, they've given her a 2013 C300 4matic sport as a loaner. I put 200+ miles on it today and I like quite a bit. The trans programming seems more responsive/lively compared to our '08 and of course it has a little more oomph since it's got the 3.5 engine.

Pete7874

Got the car back. Forgot to ask them what it would have cost me had I not had the extended warranty. Excerpt from the final paperwork...

Uncle

This type of failure is not the result of service/no-service at 39K miles. I think the reason MB pushed the 39K change is partially revenue based, but also a chance to see if there is any early evidence. If seen, it would become a better controlled event, that the owner would take as extraordinary service, rather than something that never should have occurred.
On my 2WD C300, when I did the service at about 50K miles, everything looked quite good, with an even coating on the magnets.
Has anyone had these major issues with the 2WD , or is it the 4WD cars?

Pete7874

The problem is with the transfer case. RWD models don't have a transfer case, so this issue doesn't apply.

couset

My sl 63 with 6000 miles is in shop now with bad right front wheel bearing. I had same symptoms you describe.

Pete7874

Did you read the rest of the thread? It wasn't a wheel bearing in my case.

Pete7874

BTW, I was told by a service advisor this would have cost approximately $8K out of pocket.