Transmissions Failure (7 Speed Auto)
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Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
I was told that some of the C class cars ( and perhaps others) use a coolant radiator integrated with the transmission cooler. That is, they are basically one assembly separated by an aluminum/plastic (?) barrier. Obviously the lines in and out are separate. however, due to a manufacturing defect in some of these "radiators" the barrier corrodes and allows engine coolant to seep into the transmission fluid. This mixture causes the transmission to fail.
I do not have the details on the exact models, years affected nor do i recall the details of how the compromised tranny fluid causes transmissions to fail. However, i do trust the tech who told me this and MB is aware of the issue.
Perhaps Glyn or someone else could explain this failure mode? Would there be a TSB on this?
I do not have the details on the exact models, years affected nor do i recall the details of how the compromised tranny fluid causes transmissions to fail. However, i do trust the tech who told me this and MB is aware of the issue.
Perhaps Glyn or someone else could explain this failure mode? Would there be a TSB on this?
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Joined: Nov 2007
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From: Gulf Coast but not Florida
GLK350, SL63 AMG
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Joined: Jun 2007
Posts: 2,208
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From: Westmont, IL
2014 C63 Sedan
The whine on my car seemed to be getting a bit louder, but now is getting quieter, and sometimes I don't even notice it. I was driving the other day, maintained the speed at 62mph (thats the only speed the whine is noticeable) and downshifted and up shifted and the whine didn't change one bit. As I was going through the shifts there was not breaks in the whine, or change of tone. I have asked passengers and they all tell me the whine seems to be coming from rear drivers side. My previous tire on rear drivers side was cupped, and I replaced to 18 inch wheels and that's when I noticed the whine. Another memeber was able to get rid of the whine just by rotating his tires, so I'm hoping that the noise is coming from my tires and not the trans as my car is out of warranty already 
Newbie
Joined: Aug 2009
Posts: 11
Likes: 1
From: Toronto, ON
2010 C350 4matic, 10 VW Golf, 03 Pilot
Unfortunately, we, the end users have no way of knowing if the transmission fluid have been diluted/contaminated or if the transmission fluid is of the correct level as there is no tranny dipstick on these cars.
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Joined: Jun 2007
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From: Westmont, IL
2014 C63 Sedan
Newbie
Joined: Aug 2012
Posts: 3
Likes: 0
2012 GLK350 4matic
Know the last post is a couple weeks old, but wanted to mention my situation. It might help some of you, but I sure am getting nowhere with my local dealership. Bought a brand new 2012 GLK 4Matic in March. Test drove it, but in super bad traffic so we didn't get it above 20 mph. No problem, had GLK loaner cars and test drove another, so I knew what I wanted. When I drove it off the lot down a road and got it up to 40, I heard a whining sound when letting go of the gas (but not pushing the break) that I could only describe as a "whooooo" noise. Called the salesman, he said that a 4matic would be louder than my old c-class and I would get used to it.
The noise got worse, and after a 5 hour road trip, you couldn't get my husband out of the car fast enough. This shouldn't happen in a new car. It sounds like you are blowing air in a glass bottle.
Had the shop foreman drive with me, he heard it right away said it was a faulty transfer case, a replacement would solve the problem immediately, but that there was nothing actually wrong with my car, just an annoying noise.
So we brought it back to have the Transfer Case replaced. They said that my noise wasn’t loud enough for Mercedes to pay for it – that you can’t just replace your transfer case, the entire transmission has to be replaced. Then they change their story that Mercedes would pay for it, but that it could be much worse, and then Mercedes wouldn’t do anything for me, if it was much worse.
Then they said that the 4matic is much louder than a 2 wheel, and that loud whining noises are very normal with all 4matics and that I could trade it in for the RWD GLK if I wanted to. Then that maybe I would enjoy a Hyundai instead. !!! I really hate this place and am at my wits end.
Is this normal? Are 4matics loud and whiny? (I don’t believe so). Will a brand new transmission fix it or make it worse? If this happened when the car had 18miles on it, and is MUCH worse a 8k, what will happen later on? Do I just want a RWD?
The noise got worse, and after a 5 hour road trip, you couldn't get my husband out of the car fast enough. This shouldn't happen in a new car. It sounds like you are blowing air in a glass bottle.
Had the shop foreman drive with me, he heard it right away said it was a faulty transfer case, a replacement would solve the problem immediately, but that there was nothing actually wrong with my car, just an annoying noise.
So we brought it back to have the Transfer Case replaced. They said that my noise wasn’t loud enough for Mercedes to pay for it – that you can’t just replace your transfer case, the entire transmission has to be replaced. Then they change their story that Mercedes would pay for it, but that it could be much worse, and then Mercedes wouldn’t do anything for me, if it was much worse.
Then they said that the 4matic is much louder than a 2 wheel, and that loud whining noises are very normal with all 4matics and that I could trade it in for the RWD GLK if I wanted to. Then that maybe I would enjoy a Hyundai instead. !!! I really hate this place and am at my wits end.
Is this normal? Are 4matics loud and whiny? (I don’t believe so). Will a brand new transmission fix it or make it worse? If this happened when the car had 18miles on it, and is MUCH worse a 8k, what will happen later on? Do I just want a RWD?
Junior Member
Joined: Aug 2012
Posts: 26
Likes: 0
From: Fort Worth
2010 C300 Sport
Know the last post is a couple weeks old, but wanted to mention my situation. It might help some of you, but I sure am getting nowhere with my local dealership. Bought a brand new 2012 GLK 4Matic in March. Test drove it, but in super bad traffic so we didn't get it above 20 mph. No problem, had GLK loaner cars and test drove another, so I knew what I wanted. When I drove it off the lot down a road and got it up to 40, I heard a whining sound when letting go of the gas (but not pushing the break) that I could only describe as a "whooooo" noise. Called the salesman, he said that a 4matic would be louder than my old c-class and I would get used to it.
The noise got worse, and after a 5 hour road trip, you couldn't get my husband out of the car fast enough. This shouldn't happen in a new car. It sounds like you are blowing air in a glass bottle.
Had the shop foreman drive with me, he heard it right away said it was a faulty transfer case, a replacement would solve the problem immediately, but that there was nothing actually wrong with my car, just an annoying noise.
So we brought it back to have the Transfer Case replaced. They said that my noise wasn’t loud enough for Mercedes to pay for it – that you can’t just replace your transfer case, the entire transmission has to be replaced. Then they change their story that Mercedes would pay for it, but that it could be much worse, and then Mercedes wouldn’t do anything for me, if it was much worse.
Then they said that the 4matic is much louder than a 2 wheel, and that loud whining noises are very normal with all 4matics and that I could trade it in for the RWD GLK if I wanted to. Then that maybe I would enjoy a Hyundai instead. !!! I really hate this place and am at my wits end.
Is this normal? Are 4matics loud and whiny? (I don’t believe so). Will a brand new transmission fix it or make it worse? If this happened when the car had 18miles on it, and is MUCH worse a 8k, what will happen later on? Do I just want a RWD?
The noise got worse, and after a 5 hour road trip, you couldn't get my husband out of the car fast enough. This shouldn't happen in a new car. It sounds like you are blowing air in a glass bottle.
Had the shop foreman drive with me, he heard it right away said it was a faulty transfer case, a replacement would solve the problem immediately, but that there was nothing actually wrong with my car, just an annoying noise.
So we brought it back to have the Transfer Case replaced. They said that my noise wasn’t loud enough for Mercedes to pay for it – that you can’t just replace your transfer case, the entire transmission has to be replaced. Then they change their story that Mercedes would pay for it, but that it could be much worse, and then Mercedes wouldn’t do anything for me, if it was much worse.
Then they said that the 4matic is much louder than a 2 wheel, and that loud whining noises are very normal with all 4matics and that I could trade it in for the RWD GLK if I wanted to. Then that maybe I would enjoy a Hyundai instead. !!! I really hate this place and am at my wits end.
Is this normal? Are 4matics loud and whiny? (I don’t believe so). Will a brand new transmission fix it or make it worse? If this happened when the car had 18miles on it, and is MUCH worse a 8k, what will happen later on? Do I just want a RWD?
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MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,986
Likes: 6
From: SEATTLE WASHINGTON USA
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
I was told that some of the C class cars ( and perhaps others) use a coolant radiator integrated with the transmission cooler. That is, they are basically one assembly separated by an aluminum/plastic (?) barrier. Obviously the lines in and out are separate. however, due to a manufacturing defect in some of these "radiators" the barrier corrodes and allows engine coolant to seep into the transmission fluid. This mixture causes the transmission to fail.
I do not have the details on the exact models, years affected nor do i recall the details of how the compromised tranny fluid causes transmissions to fail. However, i do trust the tech who told me this and MB is aware of the issue.
Perhaps Glyn or someone else could explain this failure mode? Would there be a TSB on this?
I do not have the details on the exact models, years affected nor do i recall the details of how the compromised tranny fluid causes transmissions to fail. However, i do trust the tech who told me this and MB is aware of the issue.
Perhaps Glyn or someone else could explain this failure mode? Would there be a TSB on this?
This is well known at MB and back in the days of the W203 the model that had this failure most was the C32. Engine coolant would get into the trans and it would start malfunctioning. The dealers use a standard test of the trans fluid to see how contaminated it is and above a certain test number the trans, along with the radiator, must be replaced.
The bad radiators are made by Valeo in Italy, according to my dealer tech.
Newbie
Joined: Aug 2009
Posts: 11
Likes: 1
From: Toronto, ON
2010 C350 4matic, 10 VW Golf, 03 Pilot
Know the last post is a couple weeks old, but wanted to mention my situation. It might help some of you, but I sure am getting nowhere with my local dealership. Bought a brand new 2012 GLK 4Matic in March. Test drove it, but in super bad traffic so we didn't get it above 20 mph. No problem, had GLK loaner cars and test drove another, so I knew what I wanted. When I drove it off the lot down a road and got it up to 40, I heard a whining sound when letting go of the gas (but not pushing the break) that I could only describe as a "whooooo" noise. Called the salesman, he said that a 4matic would be louder than my old c-class and I would get used to it.
[COLOR=black]The noise got worse, and after a 5 hour road trip, you couldn't get my husband out of the car fast enough. This shouldn't happen in a new car. It sounds like you are blowing air in a glass bottle. [/COLOR
Had the shop foreman drive with me, he heard it right away said it was a faulty transfer case, a replacement would solve the problem immediately, but that there was nothing actually wrong with my car, just an annoying noise.
So we brought it back to have the Transfer Case replaced. They said that my noise wasn’t loud enough for Mercedes to pay for it – that you can’t just replace your transfer case, the entire transmission has to be replaced. Then they change their story that Mercedes would pay for it, but that it could be much worse, and then Mercedes wouldn’t do anything for me, if it was much worse.
Then they said that the 4matic is much louder than a 2 wheel, and that loud whining noises are very normal with all 4matics and that I could trade it in for the RWD GLK if I wanted to. Then that maybe I would enjoy a Hyundai instead. !!! I really hate this place and am at my wits end.
Is this normal? Are 4matics loud and whiny? (I don’t believe so). Will a brand new transmission fix it or make it worse? If this happened when the car had 18miles on it, and is MUCH worse a 8k, what will happen later on? Do I just want a RWD?
[COLOR=black]The noise got worse, and after a 5 hour road trip, you couldn't get my husband out of the car fast enough. This shouldn't happen in a new car. It sounds like you are blowing air in a glass bottle. [/COLOR
Had the shop foreman drive with me, he heard it right away said it was a faulty transfer case, a replacement would solve the problem immediately, but that there was nothing actually wrong with my car, just an annoying noise.
So we brought it back to have the Transfer Case replaced. They said that my noise wasn’t loud enough for Mercedes to pay for it – that you can’t just replace your transfer case, the entire transmission has to be replaced. Then they change their story that Mercedes would pay for it, but that it could be much worse, and then Mercedes wouldn’t do anything for me, if it was much worse.
Then they said that the 4matic is much louder than a 2 wheel, and that loud whining noises are very normal with all 4matics and that I could trade it in for the RWD GLK if I wanted to. Then that maybe I would enjoy a Hyundai instead. !!! I really hate this place and am at my wits end.
Is this normal? Are 4matics loud and whiny? (I don’t believe so). Will a brand new transmission fix it or make it worse? If this happened when the car had 18miles on it, and is MUCH worse a 8k, what will happen later on? Do I just want a RWD?
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,986
Likes: 6
From: SEATTLE WASHINGTON USA
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
It's the other way around. The trans cooler is a separated part of the radiator and as far as I know all cars and trucks with auto trans have had them for decades.
This is well known at MB and back in the days of the W203 the model that had this failure most was the C32. Engine coolant would get into the trans and it would start malfunctioning. The dealers use a standard test of the trans fluid to see how contaminated it is and above a certain test number the trans, along with the radiator, must be replaced.
The bad radiators are made by Valeo in Italy, according to my dealer tech.
This is well known at MB and back in the days of the W203 the model that had this failure most was the C32. Engine coolant would get into the trans and it would start malfunctioning. The dealers use a standard test of the trans fluid to see how contaminated it is and above a certain test number the trans, along with the radiator, must be replaced.
The bad radiators are made by Valeo in Italy, according to my dealer tech.
I asked my dealer's service manager about this and he said the problem has gone away. I asked for details in re: the trans fluid test for coolant contamination and he said it was a litmus test. I asked if they were doing this test now when doing trans fluid changes and he said not any more. He did say that the C32s seemed to have this happen more often than the rest.
So, this is a non-issue.
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
It's the other way around. The trans cooler is a separated part of the radiator and as far as I know all cars and trucks with auto trans have had them for decades.
This is well known at MB and back in the days of the W203 the model that had this failure most was the C32. Engine coolant would get into the trans and it would start malfunctioning. The dealers use a standard test of the trans fluid to see how contaminated it is and above a certain test number the trans, along with the radiator, must be replaced.
The bad radiators are made by Valeo in Italy, according to my dealer tech.
This is well known at MB and back in the days of the W203 the model that had this failure most was the C32. Engine coolant would get into the trans and it would start malfunctioning. The dealers use a standard test of the trans fluid to see how contaminated it is and above a certain test number the trans, along with the radiator, must be replaced.
The bad radiators are made by Valeo in Italy, according to my dealer tech.
Newbie
Joined: Aug 2012
Posts: 3
Likes: 0
2012 GLK350 4matic
They said that I would be deciding to replace the transmission, with full understanding that it could get worse. If it did get worse, Mercedes would not put the old transmission in, that I would be left with a worse noise. Or would just need to trade in my car for a different one (I am SURE at my expense).
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,986
Likes: 6
From: SEATTLE WASHINGTON USA
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
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Joined: Sep 2009
Posts: 2,108
Likes: 7
From: Dix Hills, New York
2012 C250 Coupe
Just came across this thread... I no longer have my 2009 C300 4Matic, and now have a 2012 C250 Coupe. I had this "howling noise" since my C300 was new, and had it up until 45,000 miles. Had no issues with my vehicle or transmission. Perhaps it is just the 4matic system being loud/creating resonance. Like the rest of you, I would ALWAYs hear this on the highway at around 60-62mph - especially when I was coasting. I would also hear it when coasting at a slower speed, I want to say around 32-40mph.
Neither of our two 2012 RWD C250 Coupe with the 7G tronic plus transmissions do not experience this howl. However, our remaining 2011 C300 4matic does. So this leaves me to believe that the noise comes from 4matic - or possibly just the nature of the C300 engine, but not the actual transmission itself.
Neither of our two 2012 RWD C250 Coupe with the 7G tronic plus transmissions do not experience this howl. However, our remaining 2011 C300 4matic does. So this leaves me to believe that the noise comes from 4matic - or possibly just the nature of the C300 engine, but not the actual transmission itself.
Newbie
Joined: Feb 2013
Posts: 4
Likes: 0
From: Midwest
2009 C300 Sport [work/weekends]; 2011 Camaro RS [summertime]; 2012 Lexus GX460 [snow, cargo, dogs]
I noticed the howling shortly after I purchased my 2009 C300 4matic. I purchased it CPO in early 2012. The MB Dealer took it for a test drive and suggested that it was the transfer case and replaced it under warranty. Funny thing is, the 2012 c300 4matic loaner they gave me while they were doing the work made the same sound at highway speed. After the transfer case swap, it did seem to get better, but, I still hear the noise from time to time. Does sound like a very annoying, less than optimal trait of the 4matic system.
Senior Member
Joined: Apr 2010
Posts: 410
Likes: 2
From: Orlando FL
2009 C300 4Matic Sport
The bad new is that all w204 4matic cars have a transmission and a transfer case in one piece. They cannot be replaced separately
Last edited by ggms16; Feb 11, 2013 at 11:32 PM.
