Help diagnosing a problem
 

Hello everyone. First time poster....long time lurker. Over the past year or so, I have come to rely heavily on everyone's expertise in dealing with matters for my 2003 X5 3.0l. Recently, an issue arose with my X5 that has me completely perplexed.....so I need some advise.

About two weeks ago I was slowing down for a stop light and I heard a horrible noise coming from my front end that sounded like a wheel bearing that has completely failed. The noise starts at around 8mph and doesn't go away at any speeds (although the noise is so loud that I haven't taken the x5 above 30mph). The noise is constant and doesn't vary in sound even if I steer left or right. I had the X5 towed to my house and start to diagnose the problem.

I've jacked it up just to find that there is no play with either front hubs or that my brakes are dragging and the pads look fine. I also found that my driver's side outer CV boot was ripped, but I don't think that would be causing the sound. I decided to go ahead and run it for a short period on jack stands to see if I could replicate the noise. The following is what I have witnessed:

1. Start car - everything fine
2. Put in drive - back wheels start to spin...everything fine
3. Push gas - front drive system engages around 10mph
4. Noise heard from front drivers side. Immediately think its wheel bearing.

Now, this is where I get confused. I did a test run before I put the car up on jack stands and I noticed that the noise went away while rolling down a slope (not pushing the gas pedal). As soon as I put some gas to it, the front drive train kicked in and the noise came back.

Shouldn't the noise be there if it is from the wheel bearing whether I apply the gas or not? Does the wheel not roll on the same bearing whether the front diff is applying torq or not? Could a torn CV boot or bad axle make that noise? Should I be looking for something else entirely like bad front drive shaft/transaxle?

Soooooooo lost. Any help is greatly appreciated!

Look between the rotor and dust shield and see if something like a rock might had gotten wedge in between them.

Thanks for the reply. I'll take a look.

No rock or anything else wedged in there. Any other suggestions?

Since your saying the noise happens when your on the gas, id take a look at the CVs make sure the splines are still ok, can be a front diff issue, or perhaps even transfer case although im not familar with the tcase on the pre xdrive ones.

Any easy ways to check these or am I ripping prions of the front end off?

front driveshaft
 

sounds like the splines on the front drive shaft have worn out.

the fix

or some people use spacers to push the drive shaft back a little further.

What kind of spacer do they use?

Also, is there a way to check for this? Drive shaft play/slop?

Lots of good info here

The best way to check is to pop the drive shaft off, the front drive shaft is under the driver side front door. If that is where the noise comes from it sounds like the culprit.

Ok. I'll see what I can find out. Thanks.

Update: I've narrowed it down to the dreaded front drive shaft spline issue. I am trying to remove the drive shaft now, but it isnt wanting to come out. I did a search for a DIY and I really didnt come up with anything. Does anyone have a good walkthrough on how to remove it?

Lots written about those drive shafts.

Start here.


http://www.xoutpost.com/bmw-sav-foru...t-problem.html

Some pics here.


http://www.xoutpost.com/bmw-sav-foru...-pictures.html

You have to decide how deep you go. You can get a new or used BMW driveshaft, and swap those out without touching the transfer case or you can get a version with longer splines from a few places. That will require at least loosening the transfer case and likely require removing the transfer case to get clearance.

Thanks. I'm going to get the extended drive shaft and go that route. My problem right now is getting the old shaft out. It seems I have to split the tray and TC to get it out. Unless there is another way I am not seeing.

If you have a standard length spline, this is the general method to get it out. You should not have to remove the TC (install with the longer splines is different).

1) Remove the 6 bolts on the front rubber Guibo.
2) Use muscle power or some sort of lever to slide the front driveshaft back into the transfer case. If the splines are really bungled up, this may be hard to impossible. Hopefully they will still slide for you.
3) After you get a little movement, you should be able to free the rubber Guibo
4) Once the Guibo is out of the way, you should be able to wiggle the driveshaft out.

Two suggestions - if you are removing the TC to replace the front driveshaft, I would check the TC chain for stretch and replace while you have the chance. They are not expensive and do stretch with use. Easy job once the TC is out of the car.

I also found that the center support bearing on the rear driveshaft was really sloppy once I started taking things apart on mine - its another wear item and worth checking.

Yeah. I'm having an issue with moving it back enough to get the Guibo out. I'll keep working on it.

Great idea on checking for chain slop while I'm at this stage.

Pry bar. You need to pry it back as it won't easily move, especially one that has lived in a place with inclement weather. Mine was a San Fran to Vegas X5 and the splines were orange colored with a light surface rust. Grease the splines when you put your new driveshaft in.

BTW: can you do to advanced edit and change the title to be more descriptive of the problem? It'll help others in the future...

And...now is a great time to put a signature (look in the User CP).