70k miles, 09 528, newer brakes, no codes
I just came home from a road trip. At 40mph, I hear a "constant moan or groan" from the rear. Up to 100mph still there. Tires fairly new. Yes the pitch changes with speed. As it drives by me, no sound detected, only audible from the inside. Inspection on tires good. Just started today on a 3hr trip. All freeway.

I had someone drive it as I sat in the back seat. The groan is below dead center of the back seat. If I read past posts correctly, no DIY for u joints? Could differential fluid be the cause?
A bearing? I don't think wheel bearing because I would think I can isolate the noise from the offending side. No excessive heat to the touch on the hubs.

Indy time? Or is DIY a possibility?

She drives great, no performance issues. I just know something is going to blow soon.

Notes: no leaks, no drain plug for differential, only fill plug. No loose play. It's actually scary clean .

 

Had this happen on my MB 190e. The rear differential seal failed and by the time it was diagnosed and repaired the unit had failed and needed to be rebuilt. Hope this isn't the case for you.

 

I was going to take her in tomorrow. The hail storm took out my windows last night.....so it will wait. Pffffffft

Thanks for the feedback

 

Right rear wheel bearing is the diagnosis. $500 from indy. Not enough time, not enough knowledge. I'm letting him do it.

 

Wow $500. I just did one 2 weeks ago and the hub assembly was only $80. It was my first time doing one but I got it done with the help of a hydraulic puller ($65). It was easy as pie.

 

Yeah, I'm sure I could do it......but I had to throw other factors in my thought process. No pain on this decision.