At 55-65 mph, I'm getting a droning noise from the back of the car and vibration in the seats, especially the passenger seat. No vibration in the steering wheel.

Had the wheels balanced and rotated, but the issue is still there.

My local mechanic recently said the rear differential seals need replacing, but I dont think that would cause a noise issue.

What are the moving parts in the drivetrain at the back of the car that could be causing this? Is it likely the early stages of the right rear wheel bearing going to pot? I'm not sure because cornering has no effect on the noise.

1998 Audi A4 2.8
142,000 miles

 

Bump please help. Thinking about replacing the right rear wheel bearing, but perhaps this is a driveshaft bearing of some sort?

 

wheels bearings, replace them on both sides cause if one is shot, the other one is probably on its way out. with 142,000 on the clock its definately them, mine went at 135,000. parts are cheap, check out esctuning.com the job itself is a little labor intensive though...

 

Thanks, Audacity. I drove at highway speed last night and the sound was more pronounced turning right, so bearing sounds right. I'll get both of the rears done.