BMW F97 Technical Training Manual page 32

F97/F98￿Complete￿Vehicle
4.￿Powertrain
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
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