330xi vibration- possible center driveshaft bearing, but no other issues

Hey all,

My 2003 BMW 330xi, 95,000miles, 6 speed, has vibration (no clunking) while under full acceleration, starting at 3500 RPM+ in any gear. I can't seem to figure out why, so I'd like to tap into all the knowledge of this forum!

Last weekend, I did the following to attempt to fix the issue:
1) Replaced both front drive shafts w/ new aftermarket units purchased from FCP Groton. (originally thought that was the "for sure" issue, did have minor clicking while turning.)
2) Front and rear diff changed with Castrol synthetic 75w-90.
3) Replaced transfer case fluid with Redline D4.

A few months ago, I installed new swaybar end links & lower control arm bushings (L & R) and had a recent mount and balance of winter tires. Everything in the suspension/brake department seems great.

At this point I'm looking further into the drivetrain. From what I've read on various forums, it seems the center bearing (usually) only fails when something else (i.e. guibo/flex plate) has failed. I've closely inspected my flex plates and they seems to be in great condition, no movement of the bolts or shredding of rubber.

My question is:
Does anyone know of the rubber supporting the center drive shaft bearing simply going bad by itself? I currently suspect the center differential bearing bushing might be bad- it has a bit of movement when I grab it. However, I'm not sure what "normal" is, Should the driveshaft be rigid at that point? Or am I not thinking of something else that may be causing my issues? I uploaded a quick video at of my center bearing & rubber flexing when I grab and pull on it. I did not totally remove the exhaust or heat shield so I had to fight to get a camera in there.

Thanks again for any insight into this issue!

If the problem is related to rpm and not vehicle speed, I would think the issue lies somewhere other than the driveshafts/differentials. Motor mounts or trans mounts possibly.

I think you're right to be looking at the center differential. A vibration in my 2001 330xi that occurred under very light throttle at 45-60 mph was finally identified as being caused by that diff. It was gradually getting worse; first started being noticeable at 125K, was one reason I got rid of it at 145K, as replacing the thing would have been pricey.

Thanks floydarogers for the suggestion. I believe the vibration is only due to RPM because higher engine speeds creates more power, and whatever is causing this vibration only shows up under higher loads. It takes much more power to get a vehicle moving than to keep it moving. If I'm at a high RPM, but constant speed, there is no vibration.

I only know of the transfer case (which is in the center) and the front and rear differential. Regardless, how was the center differential diagnosed as the issue on your car? What I don't want to do is just randomly start replacing parts. That is a PITA, plus can end up being a lot of $$$ for nothing. When I changed my transfer case fluid it was pretty dark, but no chunks or metallic items came out that I observed.

Originally Posted by stealthx1

... Regardless, how was the center differential diagnosed as the issue on your car? What I don't want to do is just randomly start replacing parts...

We eliminated everything else. The shop worked on it 3-4 times, but eventually managed to narrow it down. I had two sets of tires/wheels (snow/summer), which was a big help in eliminating balance type problems. I had also replaced CABs and other suspension bits at 110K... Some other minor bits as well. And, my front diff had failed, so it was new.

I guess I was lucky that it started manifesting itself after all that stuff had been done as part of "normal" 100K-120K maintenance.

Originally Posted by floydarogers

We eliminated everything else. The shop worked on it 3-4 times, but eventually managed to narrow it down.

So what was the process your shop used to narrow it down? Generally, my personal "process of elimination" is to just start replacing parts I think may be causing the issue. That's exactly what I'm trying to avoid. I don't have a shop anyplace close to me that would even look at this car, so I perform all work & diagnostics myself.

Thanks

I can tell you that I have a *similar* problem where I get a vibration under load / acceleration, and it's definitely coming from the rear of the car. It also occurs most noticeably around 3,500-4000 RPM in 2nd gear. It's almost non-existent in other gears. I replaced the driveshaft center bearing and support last year and the rubber was indeed totally cooked, while the bearing itself was basically fine. The sound went away COMPLETELY for a while but now it's back, to a lesser degree. I was under there the other day and inspected the center bearing support; it was not torn, though it seemed to have a little more play than I thought it did when it was new. If there was an HD version I would have used it.

I think that torn rubber support was definitely causing the noise / vibration, but I am now thinking that play elsewhere in the system (motor mounts, trans mounts, diff mounts, etc) is wearing out the rubber support at a much faster rate than normal. So basically I ease off the throttle 10 % at that RPM and never hear it. If I have the exhaust off again sometime I might replace the support bearing assembly again and just ease off the throttle a bit at those speeds (I know, no fun).

So if I were you, I'd maybe try replacing that and the driveshaft/transmission coupler (aka guibo) and see where you're at.... not to throw parts at it but those aren't too bad in the grand scheme of things.

Originally Posted by stealthx1

So what was the process your shop used to narrow it down?

Multiple test drives, with riders and stethoscope. Inspections and stethoscope use on rack.

Originally Posted by 1972ford

So if I were you, I'd maybe try replacing that and the driveshaft/transmission coupler (aka guibo) and see where you're at.... not to throw parts at it but those aren't too bad in the grand scheme of things.

'72Ford- I replaced the center driveshaft bearing over the weekend with a new OEM bearing/carrier. While I was down there, I checked the rear guibo (it was in great shape), and moved the disconnected driveshaft in various directions to see if there was any play/binding/etc from the u-joints- there was not, they also seem fine.

I put everything back together and was really not too surprised to find the exact same vibration under heavy acceleration issues I was trying to resolve. I was skeptical because the new center bearing/carrier had similar flex in the rubber to the unit I just replaced. It is apparent to me now that the bearing carrier rubber movement I thought was excessive was in fact normal.

Originally Posted by floydarogers

Multiple test drives, with riders and stethoscope. Inspections and stethoscope use on rack.

Floydarogers- did you notice any metal particles in the center diff fluid when you changed it to suggest failure of that component? I'm still trying to get to the bottom of this issue!


Thanks all!

Originally Posted by stealthx1

Floydarogers- did you notice any metal particles in the center diff fluid when you changed it to suggest failure of that component? I'm still trying to get to the bottom of this issue!

No, didn't see any shavings. And I had the diffs/tranny fluids changed at regular intervals, too. I had my front diff break a tooth and lock up at around 120K; thinking that that contributed (bent shaft?) to the center diff going...

Originally Posted by stealthx1

I put everything back together and was really not too surprised to find the exact same vibration under heavy acceleration issues I was trying to resolve. I was skeptical because the new center bearing/carrier had similar flex in the rubber to the unit I just replaced. It is apparent to me now that the bearing carrier rubber movement I thought was excessive was in fact normal.

Bummer. In my case the existing carrier had torn rubber, so it was obviously bad. But, like you, I still get the vibration sometimes, but not always. That's what's so frustrating about it!

Originally Posted by stealthx1

'72Ford- I replaced the center driveshaft bearing over the weekend with a new OEM bearing/carrier. While I was down there, I checked the rear guibo (it was in great shape), and moved the disconnected driveshaft in various directions to see if there was any play/binding/etc from the u-joints- there was not, they also seem fine.

I put everything back together and was really not too surprised to find the exact same vibration under heavy acceleration issues I was trying to resolve. I was skeptical because the new center bearing/carrier had similar flex in the rubber to the unit I just replaced. It is apparent to me now that the bearing carrier rubber movement I thought was excessive was in fact normal.



Floydarogers- did you notice any metal particles in the center diff fluid when you changed it to suggest failure of that component? I'm still trying to get to the bottom of this issue!


Thanks all!

So the play you see in that vid the OP posted does not look excessive? I think most of us XI owners with the mileage we have on our cars now are experiencing these issues. If that does not seem like excessive play than maybe the answer lies in the easier to change, probably time to change anyway, motor mounts and tranny mounts.
I know you are trying to avoid unnecessary parts replacement but it seems as though you are going about it in the correct fashion. As stated even shops have trouble diagnosing problems sometimes. I always take heart in the fact that I am able to change almost any part myself so I am saving the labor.
Please keep us posted on how you make out with this problem as I am sure all XI owners are interested.
Tommy T

So you did replace the front axles? Since you said "both driveshafts" I'll assume thats what you meant. Did the vibration change in any way after the FCP axles were installed? IF it did its probably still the axles. Many have had issues with the aftermarket axles vibrations being a fair amount of those issues.

If you havent really changed your axles then:

The most common issue issue for vibration on acceleration symptoms in the XI are the front axles. Dry (lacking Grease) inner CV joints to be exact. You need to rule this out before trying anything else. Inspect all of the CV joints and look for rips/tears, grease leakage etc. One important aspect to note is that the joints can look perfectly fine from the outside but that doesnt mean that there is grease in there. The inner CV joints on these BMWs have a very viscous grease (more like a thick oil than grease) used in the inner cv joints. What happens is that over time the clamp on the inner joint slacks off and allows the grease to escape.

-GCoop

Originally Posted by GCoop

So you did replace the front axles? Since you said "both driveshafts" I'll assume thats what you meant. Did the vibration change in any way after the FCP axles were installed? IF it did its probably still the axles. Many have had issues with the aftermarket axles vibrations being a fair amount of those issues.

If you havent really changed your axles then:

So if there are no tears in the boots do you reccomend removing and regreasing or replace with OEM ?

Originally Posted by tttomttt

So if there are no tears in the boots do you reccomend removing and regreasing or replace with OEM ?

Just a regrease should be all that is needed in that case. Its what I have done twice now. 130k on original axles.