325iX shudder 55mph up

[H-M]

Hello, I have a slight problem with my 325iX that started pretty much "out of the blue". BTW, I have checked tire pressures and fastening :)

When I drive north of 50 mph there is quite a bit of shuddering to the steering wheel as well as the whole car (more prominent and really visible on the steering wheel). The shudder is so annoying that I have to keep the speed below 50 mph. Also when I press the accelerator pedal after coasting at speed there is a slight thump from the rear I would say. The shudder does not go away by pressing clutch, changing gears etc.

I took my iX to the garage and they found slight play from the rear differential. We took the diff out and I took it to another garage (specialising in diffs) and they said this should not cause any problems as it is so slight and once fully oiled it should not even be noticed. And the 4wd would lessen the impact even more. The internals of the rear diff were pretty much perfect otherwise except for this slight play. The car has been driven only 90 000 miles and serviced regularly.

There were no other visible issues in the drivetrain, but has any of you had similar experiences?

Thanks in advance :)

[TehRaydarlover]

Sounds like something came out of balance. Maybe one of your wheel weights came off. I'd check to see if any of them are missing. Could also be a flex disk somewhere.

[Dirty325ix]

i would agree with it being a wheel off balance...Does the wobble go away with acceleration?

if its a flex disk problem(or driveline problem) than it wouldn't be speed dependent it would be rpm dependent, for example i had a bad flex disk and the car would stutter between 3k and 4k and you would really notice it at highway speeds because it cruises around 3500 rpms on the highway

[z122643]

Does it have aftermarket rims?

If it does make sure they fit on the hub correctly. You may need spacer rings, like the ones below. Even though the rims bolt up correctly, it does not mean they are aligned on the hub correctly. (I will decline to comment on how long it took me to figure this out on my own iX)

http://www.amazon.com/gp/product/B00CH8MG64/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

[EyExR]

CABs look good?

How's the tire tread wear pattern?

Perhaps swap the front wheels to the rear and see if this changes anything...

I would also suspect the front shock mounts...

[H-M]

Thank you for the suggestions! However it seems that at least in the rear diff there is some play. The other garage says that yes, definitely this would cause at least the thump I encounter when pressing the pedal after coasting. The other one is not so sure. But both say that I will get rid of the play if I replace the lsd unit. I am thinking of replacing the viscous one with clutch pack.

Please see the video:

https://dl.dropboxusercontent.com/u/18183019/XAI-660/WP_20150313_009.mp4

[hilde11211]

I've had this problem for a while. My mechanic hasn't been much help in fixing it. Put in new drive line and thicker diff fluid, but no luck. If you happen to figure out what's going I'd be very curious to see if it's the same on my car.

[H-M]

Actually the problem seemed to be partly seized front brake. There is the "slider" that was not working correctly. Now the shudder is away and the diff works okay despite the play :) Lots of investigation because of a very trivial problem but at least I can drive without the shudder now..

[EyExR]

Nice!

[2002tiiguy]

i getting a bad shutter at 100+mph (yes i know, shut up) ive also been having some brake issues, gonna rebuild everything up front on the brakes and see how it goes.