rumble when turning
It is barely audible and more a feeling in the seats - like if you were to drive on those highway anti-sleep bumps, but not anywhere close to that severity. I want to say it feels like something in the rear but not sure how that would be possible. Visually nothing weird is happening at the belts. Any ideas?
As a history, we did have the original alternator replaced last year after it started making squealing noises. Apparently there's some noise at start-up now too but goes away quick, though I didn't hear it this time. Could this all be some drive-belt related?
Last edited by rh71; Mar 30, 2014 at 12:19 PM.

I believe they are Conti's. Are the C300 sport tires uni-directional or staggered even in the slightest? Doesn't mention it on the C300 manual found on the web which isn't surprising. Should we be doing 2 fronts to the back but 2 rears criss-cross to the fronts?
Last edited by rh71; Mar 30, 2014 at 05:07 PM.

Trending Topics
The Best of Mercedes & AMG
If it is this, what do you think the repair cost may be? Sounds like it's within the transmission - hope this doesn't mean they need to take it apart and rebuild. I think the powertrain warranty was 4 years which we've just passed in Sept.
Last edited by rh71; Apr 1, 2014 at 06:49 PM.

Conti SC Tyres make a noise from new which gets worse with wear. I threw them off my W203 at 15,000Km much less 14,000 miles due to noise (like a bad wheel bearing) & rumbling when turning. Pity you can't borrow a set of wheels with other tyres mounted & try them.
If you are convinced it's not tyres then go & do many figure of 8's & see if this improves things as suggested. On 4Matics with transmission issues I'm always very aware that the noise is from the transmission & not the wheels.
245/45/17 and 245/40/17. Would it be ok to swap them front to back anyway? The middle number is the profile size (sidewall)... shouldn't matter THAT much should it?

You can't rotate front to rear. Only across the same axle to change rotation. Once these tires are noisy rotation seldom helps. You really need to rotate approx every 8K miles to keep Conti's half quiet.
If it is this, what do you think the repair cost may be? Sounds like it's within the transmission - hope this doesn't mean they need to take it apart and rebuild. I think the powertrain warranty was 4 years which we've just passed in Sept.
We're in LI, NY.







