Wheel bearing problem or worse?

[frumpy_uk]

Guys
my 325i touring makes a low rumbling noise at low speed. The sound is coming from the rear of the car. It is most noticeable between 20 & 30 mph. Doesn't seem to be dependant on what gear I'm in, or freewheeling in neutral, or what the revs are, or clutch in/out.

Sounds like a wheelbearing noise, but it doesn't seem to come from any particular side of the car.

Any ideas? Could the diff be on its way out?

cheers
Paul

[Toby_Unna]

don't take this as concrete, but a worn diff usually makes a different noise on- and off-load, if the noise stays the same when you come off then go back on the throttle the diff probably isn't an issue.

[Richy325iTouring]

Noise under lload its the diff.
Noise continuas its the wheel bearing

[Davenotouring]

Jack up the back of the car and try rocking the wheels top to bottom, see if there's any play, also spin them and listen for grumbling noise.

The diff could make noise on or (not exclusive or) off load, sometimes louder on overerun. If it is silent on a balanced throttle, I'd say it's the diff.

[frumpy_uk]

Thanks a lot guys I'll let you know how I get on

[Jon_Bmw]

Sounds strange, but check the handbrake shoes. I had a scraping sort of noise, went to the hassle of changing the diff and the noise still persisted. As davetouring suggested check the wheel bearings too by the method he described.

To check if its the shoes makeing the noise, take the wheel off, then take the caliper off, spin the disc and listen for any scraping noise. Then take the handbrake shoes out and put the disc back on and spin it, if it makes no noise you know the handbrake shoes are at fault.

Its probably more common on autos as the handbrakes arn't used as often as people just bung them in park. Mine was an auto.