Diagnosis help... e30 325i noise from the rear?!

[Lidless]

Hi all,

I have a 325i coupe - by far the best e30 I have owned to date! Lovin' the thing. However... I have a slight wine/rub/wirr coming from the rear. From my forum searches I'm thinking it's probably...

a) Wheel Bearing (hopefully!)
b) Differential (something to do with rack+pinion I read somewhere?)

The noise is not present when stationary, and the 'sound revolutions' increase with the spead. Wether I put the thing in gear, or leave it in neutral and roll, it's still there!

So I'm really in need of some help/advice. Is there anyone on the forum (more mechanically savvy than I am) that can lend me a few minutes to have a listen? I don't want to drop it off at the shop and pay $200 for them to tell me something most of you guys could probably tell me for the price of a six pack! I live in Balwyn, Melbourne, and I'm happy to drive to meet someone not too far away who might be able to help.

Thanks guys,
Tom

[e30savant]

I had the same thing going on in my car. Best way to tell if it is the wheel bearing is to jack up the rear of the car and shake both the rear wheels.
Make sure to give the tires a real good tug in every direction, if you feel any sort of movement coming from the hub it is most likely the wheel bearing.

While you have the rear tires off the ground you can get under the car. (Try to keep your head close to the diff. so you can hear any grind, movement, etc.) Now grab one of the tires if you can, or have someone help you, to run the tire either direction and listen for the noise that your hearing.

If the noise is indeed coming from the diff. first try doing a diff flush and refill. Very easy just two plugs that require a hex wrench on the back side of the diff. One for filling and one for draining. Drain first then fill with the appropriate gear oil. Make sure that you use a limited slip additive or LSD gear oil if you have a Limited slip rear differential.

Hopefully that will help some. The noise never completely went away on my car but it is much less noticeable than it was before.