BMW F97 - Page 32

F97/F98�Complete�Vehicle
4.�Powertrain
28
4.3.1.�Four-wheel�drive
The�M�xDrive�system�used�on�the�F97/F98�is�based�on�the�all-wheel�drive�system�of�the�G12�with�the
ATC13�transfer�box�and�has�been�carried�over�from�the�F90.
The�torque�generated�by�the�engine�is�stepped�up�in�the�automatic�transmission�and�is�supplied
via�the�transmission�output�shaft�to�the�transfer�box.�The�transfer�box�forming�the�next�stage�in�the
drivetrain�has�the�task�of�varying�the�torque�distribution�between�the�front�and�rear�wheels�across�the
full�range�from�0:100%�to�100:0%�as�demanded�by�the�driving�situation.�Since�a�rigid�connection�of
the�rear�axle�with�the�front�axle�is�not�possible�due�to�possible�differences�in�the�wheel�speeds,�there
is�a�multidisc�clutch�inside�the�transfer�box.�The�multidisc�clutch�performs�the�task�of�variable�torque
distribution�between�the�two�drive�axles.
General�information�on�BMW�xDrive�can�be�found�in�the�product�information�publication�"ST1501�G12
Drivetrain".
4.3.2.�M�VTG�system�wiring�diagram
F97/F98,�M�transfer�box�system�wiring�diagram