Strange pulsating vibrations

[bmwz750]

Hello everyone, I hope you're all doing fine!

The car is BMW G11 2018, 750d xDrive with 175.000kms on the clock.

I started experiencing very strange vibrations on the steering wheel, floor and even drivers seat. For instance, city driving ~60kmh (1000rpms) - I can feel vibrations on the steering wheel. Please note that the steering wheel is not shaking or anything like that - but instead vibrating.

Then on higher speeds, above 100kmh, I feel pulsating vibrations on the steering wheel, vibrations on the floor and even my seat. The vibrations only get stronger as the speed goes up. It almost feels as if the car is falling apart and its really uncomfortable. Other than that - everything else is fine with the car.

The car is breaking perfectly fine - I've recently replaced brakes at the BMW as a part of regular maintenance. Tires are brand new, Continental, 3 weeks old. Wheels have been inspected numerous times and rebalanced numerous times which did not change anything. They are not even bent and each wheel required only 15-35 grams of weights for balance.

My setup is: Style 647M 19'' - 8.5J all around with 245/45/19 run flat tires.

All the suspension components have been inspected as well and nothing was wrong with it. I even done the alignment at the BMW.

Has anyone ever experienced anything similar and how did you solve it? The BMW dealer does not seem to know what the issue is.

Thanks!

[Markr]

I had a very similar issue on an Audi A8L, along with a speed related drone, which the dealer could not initially diagnose, even with expensive test kit from Germany. Eventually, they put a new car on one ramp, mine on the other and went systematically through everything and only thing that had marginally more play was the propshaft. Audi Germany authorised the replacement and problem solved. Took them weeks to diagnose, but they kept me in new A8’s throughout. May not be your issue, but something to explore. Good luck!

[Markr]

One further point, was the problem there before you changed your brakes and tyres? Just need to discount any changes that you have made.

[dbow09q]

Originally Posted by bmwz750

Hello everyone, I hope you're all doing fine!

The car is BMW G11 2018, 750d xDrive with 175.000kms on the clock.

I started experiencing very strange vibrations on the steering wheel, floor and even drivers seat. For instance, city driving ~60kmh (1000rpms) - I can feel vibrations on the steering wheel. Please note that the steering wheel is not shaking or anything like that - but instead vibrating.


Has anyone ever experienced anything similar and how did you solve it? The BMW dealer does not seem to know what the issue is.

Thanks!

Did you figure out what the problem was? I'm having a similar issue on a 2018 740i xdrive. I've replaced tires, rear pads and rotors and had an alignment so far. About to check control arms, etc. next.

[finestbm@gmail.com]

Hi
Check this post about transfer case oil
https://g05.bimmerpost.com/forums/sh....php?t=2046537
I had similar issue on my g12 and after replacing transfer case oil everything came back to normal
Also you can find some information here
https://static.nhtsa.gov/odi/tsbs/20...76367-9999.pdf

[bmwz750]

Originally Posted by dbow09q

Did you figure out what the problem was? I'm having a similar issue on a 2018 740i xdrive. I've replaced tires, rear pads and rotors and had an alignment so far. About to check control arms, etc. next.

Hi, so last week the official BMW service has replaced engine mounts as they were pretty certain that this is the issue. However, new engine mounts solved vibrations at idle and "normal" driving at speeds up until 115kmh.

With new mounts, its almost impossible to tell if engine is on at idle. Seat and floor vibrations have been eliminated at all speeds, however the steering wheel is still vibrating like crazy on speeds 125kmh+.

Ride at speeds bellow that is perfect! But its quite depressing on the highway with the vibrating (not shaking) steering wheel. The BMW service cant figure it out. They assured me that everything else with the car is in perfect order like: suspension components, drive shaft, guibos...

I will ask them about the transfer case oil and get back to you...

[dbow09q]

Originally Posted by bmwz750

Hi, so last week the official BMW service has replaced engine mounts as they were pretty certain that this is the issue. However, new engine mounts solved vibrations at idle and "normal" driving at speeds up until 115kmh.

With new mounts, its almost impossible to tell if engine is on at idle. Seat and floor vibrations have been eliminated at all speeds, however the steering wheel is still vibrating like crazy on speeds 125kmh+.

Ride at speeds bellow that is perfect! But its quite depressing on the highway with the vibrating (not shaking) steering wheel. The BMW service cant figure it out. They assured me that everything else with the car is in perfect order like: suspension components, drive shaft, guibos...

I will ask them about the transfer case oil and get back to you...

Hello, any update on if the transfer case oil change worked for you?

[krautmeister]

Also check the “Guibo” flex joint on the driveshaft. They are prone to cracking and maybe yours is worse off… especially with a diesel model with more torque. Mine was cracked and I only have 40k miles on mine.

My 550i had similar vibrations under load and now looking back on it… I’ll bet the guibo was broken on that.

[krautmeister]

Also… is it possible you hit a pothole and have bent wheels? These cars are notorious for bending rims.

[bmwz750]

Originally Posted by dbow09q

Hello, any update on if the transfer case oil change worked for you?

Hi, I've done full oil+filter service for transmission/transfer case and still have the same problem. Nothing really changed but I have a fresh oil and filter at least.

Regarding Guibos, the dealer assured me that both guibos are fine including the central driveshaft bearing with bushing.

I have checked my wheels for the 4th time the other day. All 4 are in excellent condition, not bent whatsoever. All 4 have been balanced on the Hofmann machine with 15-15 grams each. So it must be something unrelated to that...

The suspension components all seem perfectly fine.

My personal opinion is that something is wrong on the driveshaft. Either guibos or the central bearing bushing. I am going to insist to have this inspected in more detail and maybe even try to replace those parts. They've also inspected rear diff bushings and said they are in good condition.

[painintheglass]

Guibos was going to be my first guess as well. Curious to know the cause.

[bmwz750]

I have scheduled replacement of front & rear guibo and driveshaft center support bearing, at the official dealer for end of this month. I'll update here with the results.

[JellyStyle]

read the attached, BMW recall on what you are seeing.

[bmwz750]

Update:
The dealer has replaced parts on the drive shaft but no improvement whatsoever except that the car is not as loud on the highway now. It appears that the driveshaft carrier bearing was on its way out anyway.

We have no more ideas. Every single part on the car was inspected numerous times and it is in super solid condition. I am replacing my summer set and putting on new non-runflat tires this weekend. I've ordered Michelin Pilot Super Sport * to try them out.

Lets see how that goes...

Another suggestion from the dealer is to replace the side shafts. Even though they say current ones are in good condition but they might be the root cause of the issue. Its hard to decide because the offer to replace them is too much.

Originally Posted by JellyStyle

read the attached, BMW recall on what you are seeing.

Thanks for the suggestion. I've showed this to the dealer but they say its not related. xDrive unit was actually replaced 25.000km ago in warranty. The car had no issues until now.

[bg12]

Have them put it in the air and take a video of the wheels moving from under the car while viewing the interior of the wheel/wall. For approximately $1K they should straighten all wheels and then balance them to help remove any vibrations. Hope that helps too!

[bmwz750]

Another update:

I've put on my summer set 20'' with brand new Michelin Pilot Super Sport * (not run flat) and the balance has been done by experts using Hoffmann machine. All wheels are perfectly straight (0-15 grams of weights at most).

No results, so its not about the wheels. Same vibrations with my winter set 19'' (run flats).

Its been a while and the problem is still not resolved. Its depressing to cruise on the highway with such vibrations. The official BMW dealer is out of ideas as everything on the car has been inspected 10 times already.

I have received a recommendation to change transmission oil as it might be the root cause of this issue. Its never been changed before. Any thoughts on this?

[Raimo5]

Are those vibrations always starting at same or similar speeds with same frequency? Also, how do those vibrations evolve? Do they progressively get worse as you speed up or are there gaps in between where vibrations lessen? Are vibrations synchronized to road speed or engine RPM?

Also, I would have dealer do the transfer box disconnect diagnostic procedure. It can be deactivated temporarily with computer so it is an easy job in order to eliminate that possibility. Especially as they are out of ideas anyway. What is there to lose?

[bmwz750]

Hi, I will let the dealer know about the transfer box disconnect procedure. Thank you!

About vibrations:

60-100km/h - you can feel the steering wheel slightly vibrating (not shaking!).

100-140km/h - vibration becomes noticeable on the floor and seats for the driver and passenger side as well.

150-220km/h - steering wheel, floor and seats are vibrating so much that its unbearable. When it first started happening, my first reaction was to pull up and call towing company as I thought that my car was falling appart.

220km/h+ smooth car. No noticeable vibrations.

It does not depend on RPM, just speed. So the dealer thinks its side shafts (CV joints inner and outter) - but the offer is way too high for this "guess".

[Raimo5]

Well, that is a tough one. Seeing as it happens in such a wide speed range and is progressive means it has to be a rotating component. Suspension harmonics would not be applicable in such a wide range.

CV joints on output shaft can cause all kinds of vibrations but that is usually accompanied by visible wear and slack in the joints. It can be inspected with bellows removed. I would also expect a change in force of vibration between on an off throttle. On throttle should exacerbate the issue as power is sent through the shafts. That of course depends on what the transfer box is currently doing and how much drive is sent to front wheels.

Perhaps there is a trusted indie in your area who could give a second opinion on it?