I have had the dynamic drive malfunction a couple of times this past 2 years and recently had it. Took it to dealer and like the other time my "fluid was low" so they topped it off and I never have problems after that. I looked on my receipt and only saw power steering fluid that was topped off and then a seperate line that mentions to check dynamic drive. I cannot see how one would be connected to the other but heck you never know, so that is my question?

Second, how does the dynamic drive sway bar work as far as, what does it sense and how does it sense the need for stiffening the bar and how exactly does it stiffen the bar?

 

I'm 99% sure there is an explanation on the BMW site... I read it on BMW magazine a while ago.