How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Steve Your Own Question
Steve
Steve, BMW Expert
Category: BMW
Satisfied Customers: 24175
Experience:  BMW Expert
26942375
Type Your BMW Question Here...
Steve is online now
A new question is answered every 9 seconds

2002 325xi. The drivetrain has a distinct (no doubt about

This answer was rated:

2002 325xi. The drivetrain has a distinct (no doubt about it) audible and physical rumbling that changes frequency with the speed of the car and occur from shortly after starting to move and ends abruptly at about 20 mph. Seems to come from under car but hard to tell. Does not happen always but usually. Was told it might be a driveshaft bushing. No other symptoms, runs smooth at higher speeds. Can you identify what this is?
Does the car have to be in motion for the noise to occur or will it make the noise of the rear is off the ground?
hello?
will the noise occur with the rear off the ground?
Customer: replied 27 days ago.
Sorry, got called off to work. Have not checked with the rear off the ground. By off the ground I would need to jack up the rear and put car in drive? This is an XI. Will the front wheels possibly pull the car off the jack?

Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you

apologies I missed that it was an XI, no you can't run it with the front wheels on the ground, all wheels would need to be raised.

in any event, as I am sure you can apprecaite it is very hard to identify a noise that one has not heard first hand

based on your description, I would suspect a drive shaft, differential, or transfer case issue as the source of the noise.

ultimately, it won't be possible to identify with certainty until the vehicle is raised and the noise traced with a mechanics stethoscope

if you need a good non dealer option to cut down on costs, check out www.bimmershops.com or www.bimrs.org for options.

Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle...

Customer: replied 26 days ago.
Please see my question about jacking up the rear of the car. I want to answer your question about if the sound and rumbling still occur but again, this is an all wheel drive car and I'd rather not drive off the jack.
please see my answer above: "apologies I missed that it was an XI, no you can't run it with the front wheels on the ground, all wheels would need to be raised."
Please do not forget to click a positive rating
Customer: replied 26 days ago.
Ok. I'll get the whole car airborne. What should I know if the rumbling remains or fully disappears? Can you send me your thoughts on what to check at that point?
Customer: replied 26 days ago.
Sorry, I reread your prior note. This sound, rumble is pronounced. But abruptly disappears at about 20 mph. I don't see the differential or transfer case reacting so quickly with the problem on and then suddenly off. What is inside these two components that could react that way? But the drive shaft could possibly go from being off center from a worn bushing to centering itself as it speeds up. Make sense? But you do not specifically recognize this problem?

hi, since it is an xi, all wheels will be moving when the car is off the ground so the rumbling will occur, so it is a moot point. Again apologies for initially missing that it was an xi.

Please do not forget to click a positive rating

I cannot identify a noise I can't hear, it just isn't possible. the gearing inside a tcase or diff can make noise at certain speeds / frequencies depending on the defect. There is no way to guess at the cause without raising the car, running it, and tracing the noise with a stethoscope. Please do not forget to click a positive rating

Steve and other BMW Specialists are ready to help you