Weird vibration from right rear tire at 40MPH uphill

[michaelscooots]

Hi everyone,

We have a 2004 C320 4matic wagon with 63K. We bought it in February and pretty much immediately thereafter we had new Michelin tires installed. Before doing so we noticed a noise that came from the rear right tire. It only happens when the car is going up an incline at roughly 40 mph. The sound is sort of like the sound you'd hear when going over a grated bridge (pulsating only for a few seconds from the one tire in the rear). If I accelerate or slow down it goes away.

Once we put the tires on the noise didn't go away but the tire shop pointed out that we had a significant dent on the inner right rear rim (who knows how long it was there as we just acquired the car). I found a replacement rim online and had them put it on the car. Anyway, the noise is still present from the rear right wheel/tire.

Any ideas as to what could cause this noise? Could it be a sensor of some sort...again, this is a 4matic model.

thanks,
Michael