I hear a humming noise in the rear when driving my 2001 BMW 325I. Stops when in neutral. gets louder as I excellerate

Humming Noise Front End- Any Ideas? - Ford Explorer and Ranger ...

www.explorerforum.com > ... > Stock 1995 - 2001 Explorers

Dec 18, 2008 - 19 posts - ‎16 authors
Have a 98- Eddie 4.0 SOHC, 4WD with a 100,000 mi. When driving it has a humming noise, it almost sounds like a bad tire, or a ... I start to hear the humming noise at 20 mph, it is very loud at 40 to 50 mph ... 94 XLT-95 FX4. humming gets louder as speed increases
19 posts
May 27, 2010
How to: IAC valve cleaning thread (w/pics)
19 posts
Oct 29, 2007
humming from air intake
19 posts
Jun 6, 2002
Loud humming noise coming from the air filter
9 posts
Oct 6, 1999
More results from www.explorerforum.com

I would check for a bad wheel bearing on the rear, also check the u-joints on the drive shaft.

Might be a vaccum leak in the engine.

Probably rear brakes. Clean them up or get them looked at and try again.

It sounds like a possible wheel bearing failure.Get it checked at a local repair shop ,or possible loose bearing hub.

check you tires ( inside wall ) if there good then you might want check your rear wheel bearing if its a humming noise and gets louder as you go faster ,,good luck ,,,Joe

It could be a unevenly worn tire or a bad wheel bearing.

you may be low on gear oil...have someone check it for you before the rear end locks up

I had the same thing happen, it was the wheel bearing. It's still costly, it has to be pressed in and old one out.

If it's a regular noise that gets faster as the car is rolling faster, then chock the front wheels, jack up the back of the car, spin both rear wheels and see if you get the sound.  You may be able to pin point the location this way.   Sounds like it's somewhere in the drive train and you'll be able to hear it by spinning the wheels or the driveshaft, but if not ... you will have gotten some much needed exercise jackling the car up and down ;~).  

Since you bimmer is rear wheel drive (more of a rarity these days) you have Universal Joints (U Joints)  that connect the drive shaft to the transmission and the differential.  When these go bad (100-150K or when the car is close to 10 yrs old) they will make clicking noises, later clunking noises and finally no noises or horrendous noise when they break ... but they will make noise for 10K miles first.

You might have to crawl under your baby and turn the drive shaft and pull push it at both ends to see if you can find play in the U Joints if you don't hear the noise at one of the wheels.  

If you're clost to 150K, I'm betting on Ujoints or one of those fancy German rubber center driveshaft mounts.


Good Luck
..ajm