BMW F97 Technical Training Manual page 34

F97/F98￿Complete￿Vehicle
4.￿Powertrain
The￿Service￿employee￿can￿move￿the￿oil￿bulkhead￿to￿the￿open￿position￿by￿means￿of￿the￿"Service
function￿>￿Transfer￿box￿VTG￿>￿Oil￿change"￿in￿the￿BMW￿ISTA￿diagnosis￿system.
Current￿transfer￿box￿oil￿recommendations￿and￿capacities￿can￿be￿found￿in￿the￿current￿documentation￿of
the￿BMW￿workshop￿information￿systems.
4.3.5.￿Active￿M￿differential
The￿active￿M￿differential￿on￿the￿rear￿axle￿is￿an￿integral￿part￿of￿the￿M￿xDrive.
This￿electronically/electromechanically￿controlled￿M￿rear￿differential￿lock￿was￿developed￿specifically
for￿the￿F10￿M5￿and￿is￿also￿used￿on￿the￿F06/F12/F13￿M6,￿F80/F82/F83/F87,￿F90￿and￿now￿on￿the￿new
F97/F98.
The￿active￿M￿differential￿has￿been￿reworked￿for￿the￿F97/F98,￿which￿specifically￿involved￿adapting￿the
rear￿differential￿housing￿to￿the￿rear￿suspension￿subframe￿of￿the￿F97/F98.
The￿M￿rear￿axle￿differential,￿size￿HAG￿225￿(crown￿wheel￿Ø￿225￿mm),￿is￿used￿with￿a￿M￿rear￿axle
differential￿lock.￿The￿system￿designation￿is￿"M￿regulated￿rear￿differential￿lock"￿and￿accordingly￿the
control￿unit￿designation￿is￿M￿GHAS.￿
The￿gear￿ratio￿of￿the￿rear￿axle￿differential￿HAG￿225￿is￿3.154:1.
This￿M￿rear￿axle￿differential￿can￿be￿recognized￿by￿an￿aluminum￿oil￿sump￿assembled￿from￿below￿and￿an
electric￿motor￿which￿is￿visible￿from￿the￿outside.
The￿HAG￿225￿weighs￿43￿kg.
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