Wheel bearing, CSB or diff noise?

[fast1eddy]

I've finally started driving my E30 after restoring it over the last couple of months. I'm getting a constant rumbling sound that increases and decreases with speed. The car is a 92 325ic with 142k miles. I'll be checking it out this weekend. What are the common failures at this mileage and how do i check these items.

[Keith M]

If the sound gets louder when turning, it's a wheel bearing.

Keith

[fast1eddy]

Sound is slightly less when turning.

[drift]

make sure the tires are not worn unevenly ,or bumpy, or prolly one of the rear rims is bent?
You can also jack the car up and try push/pull each wheel inward / outward ( 3 & 9 o'clock and 12 & 6 o'clock configuration), see if thrs any 'play' on them.

[speedaddict]

sounds alot like the wheel bearing. had the same problem on my last car, only it ended much worse, tire locked-up doin about 95 on the interstate. luckly it was at 12 am and there was 4 lanes. so i didnt get hit and love tapped the wall and got only scratches.

[evil_twin]

I had the same noise. Wasn't sure what it was... But I don't think it's my wheel bearing or my CSB. How would I tell if it was my rear diff?