Differential (???) hum at 60-65mph
04-18-2003, 04:56 PM
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C320 Sport
Differential (???) hum at 60-65mph
Posted this originally on the tech board, but maybe someone else has had this problem? I haven't come up with any hits on a search.
My C320 has a problem that is baffling me. During deceleration ONLY between 60-65mph, I'm getting a hum that sounds like it's coming from the differential. It kind of sounds like when you manually downshift into the wrong gear, but I'm not seeing increased RPM.
Any idea what this could be? The dealer replaced the fuel pump and upgraded some harness and said the problem was fixed; two minutes later on the freeway, it was still doing it. The odd thing is that it ONLY happens at about 63mph, any faster or slower it disappears, and it doesn't happen while accelerating in that range. I've been trying to get an appointment with the shop foreman to ride along with me, but every time I go in, they tell me he isn't available, etc. (The dealer is less than helpful, but that's another story...)
Any suggestions you have would be appreciated. Btw, the mileage is only 12,000 so obviously it's not a typical high mileage differential issue. And I know that differential problems usually vary with speed, but it absolutely disappears except in that particular speed range.
Incidentally, my C240 loaner had the same problem but only during acceleration and somewhere in the 50 mph range.
My C320 has a problem that is baffling me. During deceleration ONLY between 60-65mph, I'm getting a hum that sounds like it's coming from the differential. It kind of sounds like when you manually downshift into the wrong gear, but I'm not seeing increased RPM.
Any idea what this could be? The dealer replaced the fuel pump and upgraded some harness and said the problem was fixed; two minutes later on the freeway, it was still doing it. The odd thing is that it ONLY happens at about 63mph, any faster or slower it disappears, and it doesn't happen while accelerating in that range. I've been trying to get an appointment with the shop foreman to ride along with me, but every time I go in, they tell me he isn't available, etc. (The dealer is less than helpful, but that's another story...)
Any suggestions you have would be appreciated. Btw, the mileage is only 12,000 so obviously it's not a typical high mileage differential issue. And I know that differential problems usually vary with speed, but it absolutely disappears except in that particular speed range.
Incidentally, my C240 loaner had the same problem but only during acceleration and somewhere in the 50 mph range.
04-19-2003, 01:06 PM
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C320 Sport
Question answered
FYI, mleskovar answered my question on the tech board. Yay! Check it out if you're curious (or if anyone has access to the TB he's referring to!)
04-19-2003, 01:46 PM
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Mercedes C240X
nope, nothing to do with fuel pump, etc. etc.
I had the same problem with my differential. My differential would make this whining noise around 60 - 65mph. It took me seven (7) frustrating visits and one (1) complain letter to MB Canada before the dealer took my complain seriously and then replaced the differential.
After they replaced the differential with a new one on my car, the humming or whining noise that I heard around 60 - 65 mph in my car is no longer there.
The differential problem is a very common one with 2001 and 2002 C-Classes.
I had the same problem with my differential. My differential would make this whining noise around 60 - 65mph. It took me seven (7) frustrating visits and one (1) complain letter to MB Canada before the dealer took my complain seriously and then replaced the differential.
After they replaced the differential with a new one on my car, the humming or whining noise that I heard around 60 - 65 mph in my car is no longer there.
The differential problem is a very common one with 2001 and 2002 C-Classes.
