Hello Everyone,

I currently drive a 1998 C280 with close to 130,000 miles on the clock. In the last 2 months or so I have noticed a harmonic vibration when I am driving. The vibration becomes very noticeable to back seat passengers at speeds of around 80mph. I also notice it and somewhat can hear the droning noise.

I would appreciate any input form you as I do not have the cash to spend on having a shop take hours to diagnose the issue.

Regards,
Christopher

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'98 C280 White on Tan

-=Santa Bring me a C43=-

Mine will make the same noise, a 97 with 81k, but it is very faint. I do believe it is coming from the rear, and my uneducated guess is something to do with the muffler. If you are experiencing vibration in conjunction with it, It's probably driveline related. Rear diff?

I hope it is not the rear diff as I replaced no more than 15,000 miles ago.

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'98 C280 White on Tan

-=Santa Bring me a C43=-

Diff gear oil can be drained a portion saved and sent in for analysis to see if any wear metals are indicating a failure.

Since you had your rear axle changed about 15K ago, check rear lug nut bolts, not to tight?

From front of car: check motor mounts, front flex disc, mid driveshaft bearing?, rear flex disc, rear diff mounts - is the noise more noticeable with rear passengers in car?

I had a like problem on our 98 C230. Shortcut; start with the tires! Our 202 body is a lot more sensitive to tire noise than our 300E. Even tires that have no visible cups, scallops, irregular wear, and with about 50% of tread left sounded like a worsening rear differential problem to us (and to the dealer).

Coincidentally, we decided to put larger rims and tires on the car before dealing with the noise 'problem' the dealer couldn't pin down under warranty (they said it was there, but they couldn't identify the source well enough to justify rebuilding/replacing the diff.). As soon as the new tires got on the car, the noise went away. The factory Goodyears didn't have any obvious problems according to the tire shop, and still had half the tread left, but roared like a bear when on our car.

We have had 3 sets of tires on this car, and while none were as bad as the Goodyears, all of them seemed to develop a loud road noise in the rear seat area of the car at about 60-80% wear, despite religious tire rotation and spin balancing of wheels on the car.

This may not be your problem area, but doesn't hurt to check it out!

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John

2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)

Click to see 87 300E

I Sincerely Hope That I Am Not To Late & That Something Really-really Bad Has ALREADY Happened To You. Replace It!!!!!!!!(the Harmonic Balancer) I Have The Same Car 98 C280 . These Balancers Have A Factory Defect (time Bomb) Built Into Them . If Yours Was Shaking That Is Really Bad But You Can Tell If They Are Going By Looking Down On It As The Car Runs & It May Wobble Or If On Inspection You Notice The Rubber Buldging Out On It . I Didn't Believe It WhEn I Was Told Mine Was Bad But After Extensive Research I Found Out These Were Designed Or Built Defective. These Things Come Apart While Your Motor Is Running & You Can Guess The Results . Good Luck Al