Hello,

Car: 84 California 300SD

Wondering if anyone knows what is causing my vibration problem. At approx 60-80 mph when i let go of the accelerator pedal suddenly, I get this hummig noise coming from underneath the car..from the chasis...feels like something in the driveline is rubbing. It goes away, if the accelerator is depressed again.

I checked the condition of the transmission mount, that looks okay and none of the exhaust hangers are loose.

Only recent driveline work was a new differential installed about 6-8 months ago.

Any ideas on what to check?

Thanks

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1) 84 300SD 285K+ Miles (Ver Calif)
2) 84 300SD 175K+ Miles (Ver Federal)

Check center support bearing, Differential mount, and flex discs.

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Bob D.
Parrish, FL
1 SDL, 1 D, 1 TD, 1 Mog

Greetings,

I think the previous post is right on track, but if you find nothing amiss there, don't forget to check the tires for proper inflation, especially if a cold spell has hit you lately.

Charles

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"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

The rubber support for the center bearing is old. If you push the rear section of the drive shaft toward the front too much during replacement of the differential, you can easily damage the rubber. The rubber is a donut shape support structure and the center bearing fits inside the donut hole.

David

I will check for this....is this an easy replacement for a DIYer or is it best left to the dealer?

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1) 84 300SD 285K+ Miles (Ver Calif)
2) 84 300SD 175K+ Miles (Ver Federal)

It is not hard but not easy either. If you have to crawl under the car to do, it may take you more than 2 hours including replacement of the center bearing. Once you have the rear shaft out, you may as well replace the center bearing and grease the areas called for by the service manual. You may have to press the bearing out of the shaft.

David

This vibration problem you speak of, Did it come about when the differential was replaced? If so the pinion gear could be out of alignment. I have run across this problem in American cars but am not sure if it holds true with the Mercedes Benz cars. ~ William

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1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4