Rhythmic Vibration

[thebmw]

When driving, especially in higher speeds, I'm noticing rhythmic vibrations from what seems to be the drivetrain. At 80 mph, the oscillations of the vibrations are spaced out around one second. That oscillation goes down as the speed goes down. This seems to be coming from the drivetrain. It is not coming from the wheels. There's no way that it could since it is once a second at 80 miles an hour. It seems to go away when I accelerate and come back when I cruise.

The vibration feels like going over very small rub strips on the road. For reference, the car is a 650 GC xDrive. I'm wondering if it has something to do with the transfer case or guibo joint? Or maybe differential? It just seems odd at the very exact spacing between the rhythmic vibrations (which is a great name for a band LOL).

[arucano]

have you had your wheels balanced lately? Strut bushing vibration is generally constant at a specific speed.

[thebmw]

Originally Posted by arucano

have you had your wheels balanced lately? Strut bushing vibration is generally constant at a specific speed.

It is happening with the summer and winter tire/wheel set. All were balanced before mounting.

I will look into the strut bushing. Never heard or thought of that. Could it be CV joints or anything else with the entire suspension?

Can the differential or transfer case cause rhythmic this vibration? It feels like it is coming from behind the driver, not in front.

[arucano]

drivetrain components will produce a constant "tone / vibration" that is proportional to speed. check if it is engine rpm dependent or drivetrain (gearbox output speed dependent to narrow it down it you think it is the drivetrain. if it is the suspension, it will generally happen at a certain speed.

[v1tal]

Hey, any update on the vibration? I have a 2-door 2015 640d with the same odd vibration.

You start feeling it at motorway/highway speeds around 60-80mph and the vibration is 2seconds vibrating and then 2 seconds almost no vibration which is odd.

I replaced guibo, have all new tyres and done wheel balancing but nothing helped

[thebmw]

Originally Posted by v1tal

Hey, any update on the vibration? I have a 2-door 2015 640d with the same odd vibration.

You start feeling it at motorway/highway speeds around 60-80mph and the vibration is 2seconds vibrating and then 2 seconds almost no vibration which is odd.

I replaced guibo, have all new tyres and done wheel balancing but nothing helped

After reading various posts, I was thinking it could be giubo. But I have now at time to get it replaced or checked out. After your post, I might be back at square one. It does seem to have something to do with the drive train and something is vibrating. Maybe a bushing or connection between drivetain and something else?

[v1tal]

Honestly I do not know what could be the issue here. I've seen it being posted by many people, but never saw a concrete solution

[racer2086]

Generally for a vibration that is coming and going like that, you are dealing with 2 vibration sources at different frequencies. The different frequencies cancel each other out and add to each other based on the overlap of the waveforms.

Tires would be the most likely for one of them. You need to find a local shop that does road force balancing. It took me many shops over the years, but I finally found one that does it right (not just says they do it) and it makes a huge difference. Most places don't take the time to measure the run out, mark the rim and tire, and then remount the tires in the correct orientation. BMW would though.

Beyond that it will take some diagnostics to narrow down the source.

[thebmw]

I will be getting it checked out this week. It could be a combination between the driveshaft center support bearing and the giubo. I don't think it is the wheels as I have swapped them out with different wheels/tires with no change. And this feels totally different and feels like it is coming from almost underneath me (right where the drivetrain is.

The rhythmic waveform is shortening in oscillation delay, implying to me that the problem is slowly getting worse.

[Alpine650]

Try putting the transmission in M/S (pull the shifter knob toward you). Or try driving in manual mode and see if it still does it. I had the same problem. 2 new wheels, 2 new tires, 12 balanced wheels, replaced quibo, replaced drive train. In shop for almost 2 months. BMW engineer came out to drive it with me on the highway. Within a minute he said it is the torque converter, but it is within spec.