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Hi,

I see from doing a number of searches on vibration that there are many, many posts relating to driveline vibration but it largely seems to be a hit and miss diagnosis exercise, often with many parts replaced and no full solution.

My car has a vibration or thrumming, drumming noise starting at about 120 km/hr and up, not heavy, but very noticeable and annoying. It sounds that it is a higher frequency than from the wheels or axle shafts.

I had the drive shaft balanced, new center support bearing and mount, and drive shaft bushings done but no difference. The flex disks were apparently OK.

I think the possible causes could include:
1. driveshaft bent or unbalanced (already balanced)
2. flex disks damaged
3. U-joint wear
4. worn centre support bearing or rubber mount (replaced)
5. driveshaft angular misalignment (transmission/front shaft ;front shaft/rear shaft; rear shaft/differential)
6. loose or worn differential mounts

Does anyone have any advice to narrow down the possible causes? Does anyone have a copy of the MB TSB on driveline vibrations that recommends addition of a damper on the differential?

I was thinking of tape recording the sound inside the car and putting it on an oscilloscope to look at the relative frequencies. One can easily calculate the driveshaft RPM vs road speed, but there may be other multiples as well, eg: 2x per rev, 3x per rev, 6x rev, based on physical geometry of flex disks and fastenings.

Any advice or experience troubleshooting and what actually worked to cure the problem(s) would be very helpful.

Very best regards,

Lisa
 

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i had this problem with my 1995 E200 coupe, vibration after 120KM. change the tires, or seal and allign the old tires if they are in good condition :)

CE200 1995
ML320 2002
 

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1985 Euro 300TD Turbo, 1983 Euro 300TD turbo, 1979 Euro 240TD and 1981 300D converted to euro.
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Having same problem, but if in drive with the brakes on at a stand still the car will make the exact vibration under load. One motor mount is new the other is shot. The flex disks and center support are fine.

So has anyone had this sound come from JUST a bad motor mount/s?

Going to change the mount either way just need the noise gone.


Car is 1995 e320 120K
 
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