I've been told, by this description, that i have a bad wheel bearing. I think there must be a better answer.
99 honda accord coup automatic.
A loud roaring vibration sound from the back. Only once accelerated. It doesn't happen from 0-10 mph. It doesn't happen hitting the gas in neutral. The noise slows and quiets down when the car is slowed down. The sound doesn't continue when turning to the left or going over bumps.
Its a loud low pitch hummm, like a piano wire vibrating from underneath. To me, its similar to peddling a exercise bike real fast and then letting it go.
This would be a wheel bearing, right? I don't understand however, why a wheel bearing would ever go bad, and why it wouldn't be a sharp metallic sound. I feel like it could be some exhaust component shaking as the car goes, maybe a loose arm or bad mount?
Help much appreciated.

 

Yes, it's most likely the wheel bearing.

 

Even before I opened your thread, I immediately thought wheel bearing and your description supports that idea. If the sound only happens while accelerating, that tells you it's part of some assembly that rotates. Also, a wheel bearing failure makes more noise the faster you go since it's doing more rotations. I could barely hear my mother's cars from 0-10mph. It's definitely not any loose mount or arm because those would make clunking noises and you would feel it.

 

Find a quite stretch of straight road, accelerate and put the car in neutral.
If the pitch of the 'humm' lowers as the car looses speed, then yes - you've a bad rear wheel bearing. It should been readily apparent if you get the car raised and hand spin each wheel individually.
How it happened? That could be open to speculation.
A seal could have failed letting water and corrosion enter, pitting the races.
A sharp impact could have marked the races when the rollers were positioned.
Both instances could cause a hum, rather than a grind noise, just as multiple playing cards in your kids bicycle spokes would change the sound.

P

 

i have the same problem, and its really bad. can someone do a Do it yourself on this problem, it would be appreciated.

 

just get a repair manual off the internet. it's free.

 

thank you raffi.