front drive line noise

Welcome to the site, I see you drive an x-drive. This means you have a front and rear differential. BMW's are notorious for noisy differentials, working at the dealership it is very common to see them fail around your mileage.

First you must eliminate wheels and wheel bearings. I know you said you already did some repairs but ensure that your front wheel bearings are not the culprit. The proper way to test is to have the vehicle driven while raised up on the hoist while listening with a stethoscope to the bearings and differential.

What did you think about no noise when backing at any speed? This is my daughters car so it will be few days before i can get it. thank you for your interest an i will get back to you.

Usually you do not hear much noise from faulty differentials or wheel bearings while traveling in reverse. The load put on the differential changes position from reverse to forward, this can change or even eliminate the noise you are hearing.

You can also check for play at the inner cv joint of the axle. Firmly grab the joint right where it enters the differential and try to shake it up and down. Do this on both driver and passenger side. Some movement is completely normal but anything over an inch is a very good indicator that the bearings inside the differential are worn out.
You should also recheck for play at both front wheels. This will test the wheel bearing. Grab and shake at twelve and six and then try nine and three. Note: just because there is no play does not mean the bearing is fine. It is one of the few tests you can perform.

going in reverse and no noise doesn't tell us something? i will have the car friday and will do what you suggested. thanks so much for your help.

One other thought... If the noise changes when turning, that usually indicates a bad wheel bearing because the weight of the vehicle is shifted.If you turn right and it gets louder, suspect the left front wheel bearing and opposite.

It is difficult to hear any noise chance, by shifting the weight of the vehicle. I would thick putting torque on the back side of the ring gear while backing would tell us something. I'll have the car friday and I will run it with four wheels off the ground. Thank each of you for being willing to help.

Today, I lifted the car off the ground and spun up the wheels. It told me nothing.I also checked bearings for play. Please continue with suggestions.

We would be able to tell right away if you can make a video of the noise and upload it here to the site. You can use a phone to do the recording. Noises are more easily fixed when we can hear the noise.

Cheers, Ken

I will give this a try thank you for the help.

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

ken, i was unable to get the sound very good using the phone. the noise want very poor. i've become familiar with the transfer assy. i'm beginning to think it could be a bearing in the transfer assy. the best way to to describe the noise, it sounds like a bad belt in a tire. it doesn't change regardless of speed, or shifting the weight of the car. any help is appreciated.

Yep I will need to go with F4I_GUY and say it is a differential that is having a problem. I would remove the Here are some diagrams to help you see what's going on. Try to isolate the noise front or rear of the car.

I would get a sample of the gear oil to see if one has more metal in it than the other this would be the differential that has the bad bearing.

Here are some diagrams (Below) to help you sew what you are in for when checking the fluid and removing the differential for service.

Check out the diagrams (Below)

Please run some tests and get back to us.

Cheers, Ken

Thanks ken, what you have listed makes a lot of sense. i've spent a lot of time reviewing you tube. ( good information). when i tried recording the noise it came to me that the noise does not chance regardless of speed. also accelerating or decelerating the noise does not chance. your interest in this situation is very important to me. Thanks.

ken, snow has hit us here in Maine so it will be awhile before i can check the car out. thanks so much for your help and interest. i'll get back to you. Marry Xmas.

Yep its tough to work in the snow on cars thats for sure. Let me know what happens, Merry Christmas!