2008 MERCEDES-BENZ GL550 differential

Contents
Control system .................................. 155
Multifunction display .................... 155
Multifunction steering wheel ........ 156
Menus .......................................... 158
Standard display menu ................ 162
AUDIO menu ................................ 164
NAV* menu .................................. 166
Off-road menu .............................. 166
DISTRONIC* menu
(Canada only) ............................... 167
Vehicle status message
memory menu .............................. 167
Settings menu .............................. 168
Vehicle configuration ................... 182
Trip computer menu..................... 184
TEL* menu ................................... 186
Automatic transmission ..................... 189
Gear selector lever ....................... 189
Shifting procedure ....................... 192
Transmission positions................. 192
Driving tips ................................... 195
Gear ranges ................................. 197
Steering wheel gearshift control .. 198
Emergency operation
(Limp-Home Mode) ...................... 200Transfer case ...................................... 201
LOW RANGE mode* ...................... 201
Differential locks* .............................. 204
A few words about differentials
and differential locks* .................. 204
Switching differential locks* ......... 205
Good visibility ..................................... 208
Headlamp cleaning system* ......... 208
Rear view mirrors .......................... 208
Power folding exterior
rear view mirrors* ......................... 209
Sun visors ..................................... 210
Rear panorama roof sunshade ...... 212
Rear window defroster .................. 212
Climate control ................................... 214
Deactivating the
climate control system ................. 218
Operating the climate control
system in automatic mode............ 218
Setting the temperature................ 219
Adjusting air distribution............... 219
Adjusting air volume ..................... 220
Air vents in the roof liner
over the second-row seats* .......... 220
Front defroster.............................. 221
Air recirculation mode .................. 222Air conditioning ............................ 224
Residual heat and ventilation........ 225
Rear climate control* ................... 226
3-zone automatic climate control* ..... 228
Deactivating the automatic
climate control system ................. 232
Operating the automatic
climate control system
in automatic mode ........................ 233
Setting the temperature ............... 234
Adjusting air distribution .............. 234
Adjusting air volume ..................... 235
Front defroster ............................. 235
Maximum cooling MAXCOOL ........ 237
Air recirculation mode .................. 237
Air conditioning ............................ 239
Using driver-side settings
for all temperature zones.............. 240
Residual heat and ventilation........ 241
Rear automatic climate control..... 241
Power windows .................................. 246
Door windows ............................... 247
Hinged quarter windows* ............. 248
Synchronizing the door windows .. 249
Summer opening feature .............. 249
Convenience closing feature......... 250
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32 At a glance
Center console
Upper part (Vehicles with enhanced
off-road package*)ItemPage
1COMAND system, see sepa-
rate operating instructions
2Climate control214
3-zone automatic climate
control*228
Rear window defroster212
3Seat heating*,
front passenger side138
4Seat ventilation*,
front passenger side140
5Rotary switch for differential
locks*205
6Switch for LOW RANGE
mode*202
7Switch for Downhill Speed
Regulation (DSR)274
8Rotary switch for vehicle
level control283
ItemPage
9Alarm system indicator
lamp110
aSeat ventilation*,
driver’s side140
bSeat heating*, driver’s side138
cAdaptive damping system
(ADS)* switch278
dElectronic Stability Program
(ESP®) switch
105
eParktronic system*
deactivation switch291
fHazard warning flasher149
gFront passenger front air
bag off indicator lamp85,
447,
448
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111 Controls in detail
Locking and unlocking
Seats
Memory function*
Lighting
Instrument cluster
Control system
Automatic transmission
Transfer case
Differential locks*
Good visibility
Climate control
3-zone automatic climate control*
Power windows
Power tilt/sliding sunroof*
Driving systems
Loading
Useful features
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159 Controls in detail
Control system
Menus, submenus and functions
Menu1Menu2Menu3Menu4Menu5
Standard displayAUDIONAV*Off-roadDISTRONIC*
(Canada only)
(page 162)(page 164)(page 166)(page 166)(page 167)
Commands/submenus
Trip- and main odometerSelecting radio stationRoute guidance
instructions, current
direction traveledCompassCalling up settings
Checking tire inflation pressureSelecting satellite radio
station*Vehicle level
Checking coolant temperatureOperating CD playerDifferential locks*
Calling up digital speedometer
or outside temperature
Calling up maintenance service
indicator
iThe headings used in the menus table are
designed to facilitate navigation within the sys-
tem and are not necessarily identical to those
shown in the control system displays.The first function displayed in each menu will
automatically show you which part of the system
you are in.
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166 Controls in detail
Control system
NAV* menu
The
NAV menu contains the functions
needed to operate your navigation system.
Press buttonè orÿ repeatedly
until the message
NAV appears in the
multifunction display.
The message shown in the multifunction
display depends on the status of the navi-
gation system:

With the COMAND system switched
off, the message
NAV Off appears in
the multifunction display.

With the COMAND system switched on
but route guidance not activated, the
direction of travel and, if applicable, the
name of the street currently traveled
on appear in the multifunction display.

With the COMAND system switched on
and route guidance activated, the di-
rection of travel and maneuver instruc-
tions appear in the multifunction
display.
Please refer to the COMAND system
manual for instructions on how to activate
the route guidance system.
Off-road menu
The Off-road menu displays the messages
for air suspension, differential locks* and
the direction into which you are currently
driving.
Press buttonè orÿ repeatedly
until one of the following messages ap-
pears in the multifunction display.Vehicles with air suspension:
Vehicles with air suspension and
differential locks*:Press buttonk orj repeatedly
until the desired setting is found.
For information on air suspension, see “Air
suspension program” (
page 278).
For information on differential locks*, see
“Differential locks*” (
page 204).
For information on the compass, see
“Vehicle submenu” (
page 178) and
“Compass” (
page 344).
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204 Controls in detail
Differential locks*
For more information on Off-road driving,
see “Off-road driving” (
page 355).
Vehicles with enhanced off-road package*
are equipped with automatic locks for the
center and rear axle differential to improve
vehicle traction.

The center differential compensates
for differences in wheel rotation be-
tween the front and rear axle.

The rear axle differential compensates
differences between the rear wheels.A few words about differentials and
differential locks*
When a vehicle negotiates a turn, wheels
on the outside of the curve must travel far-
ther and rotate faster than the inside
wheels. The differential, the operation of a
set of gears that allows the powered
wheels in a vehicle to turn at different
speeds, makes this essential function pos-
sible.
The drawback is that the differential also
sends most of the engine’s power to the
wheel with the least load or strain on it. For
example, if one of a vehicle’s powered
wheels sits on a patch of snow and spins
because there is no traction, all of the en-
gine’s power will go to that wheel because
the power will take the path of least resis-
tance. Meanwhile, the opposite wheel, sit-
ting on dry pavement where it could get
enough grip to start the vehicle moving,
sits idle because it receives no power.The Electronic Traction System (ETS) ad-
dresses this problem and provides for
good control and steering ability by auto-
matically slowing the slipping wheel and
thus increasing the power to the other
non-slipping drive wheels to get the vehicle
moving. The ESP
® and ETS in this vehicle
feature such intelligent limited-slip differ-
ential technology, ideally suited for
on-road and light off-road driving. Transfer
case position LOW (
page 201) also en-
hances off-road driving capabilities
(
page 355).
More extreme off-road conditions may call
for another solution, engaging a differen-
tial lock or preventing the differential from
operating altogether. This vehicle comes
with two differential locks: transfer case
(center) and rear. Each can be engaged
simply by operating a rotary switch located
on the center console (
page 205). When
the transfer case (center) differential is
locked, the combined (or average) speed
of the front wheels is identical to the com-
bined rear wheel speed. When the rear
differential is locked, both rear wheels turn
iAt the front axles, the 4-ETS system
(
page 107) compensates for any traction
problems.
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205 Controls in detail
Differential locks*
at the same speed, independent of the in-
dividual torque. Please be aware that en-
gaging the differential locks will
significantly reduce the steering ability of
the vehicle.
For your safety and the safety of others
and to prevent damage to the vehicle, the
differential locks must not be engaged
when driving on paved roads. It is impor-
tant to understand that during
on-road/paved driving, differentials are
absolutely necessary for providing the es-
sential control and steering ability of the
vehicle. The differential locks, therefore,
must not be engaged when driving on
paved roads and should only be used to
the extent necessary to negotiate off-road
conditions which cannot be handled by the
systems (automatic 4-ETS, the ESP
®, man-
ual switch position “LOW” of transfer case)
this vehicle comes equipped with.
Switching differential locks*The rotary switch for the differential locks
is located on the upper part of the center
console.
You can select between three locking
modes.
1Rotatable outer adjustment ring with
indicator lamp
2AUTO mode: center differential is auto-
matically locked
3Center differential is completely locked
4Center and rear axle differential are
completely locked
!If the differential locks are engaged, accel-
erate gently when setting the vehicle in motion.
To avoid damage to the transmission, the vehicle
may only be operated on a dynamometer (single
axle dynamometer) if

the axle not being driven is jacked up
or

the associated propeller shaft is disconnect-
ed.
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206 Controls in detail
Differential locks*
AUTO mode
The AUTO mode is adequate for most driv-
ing situations since the center differential
is locked and released as required.
Start the engine (page 42).
The center differential locks is in AUTO
mode. The indicator lamp on the
adjustment ring1 above
symbolU2 is on.Center and rear axle differential locksThe differential locks should only be
engaged manually if traction is insufficient
in AUTO mode.
The differential locks can be engaged in
the sequence3, 4 (
page 205) up to a
speed of 19 mph (30 km/h).
Engaging differential locks:

for off-road driving

for driving through water

when driving on deep snow and icy or
fouled surfaces
iAt speeds up to 19 mph (30 km/h), it is
possible to manually lock the differential locks
for driving on rough terrain.
Warning!G
Never drive on a paved surface with the
center and rear axle differential locks
manually engaged. Ability to steer the
vehicle is greatly reduced when the differen-
tial locks are manually engaged, increasing
the risk of an accident.
For safety reasons, the locks are automati-
cally released at a vehicle speed above
31 mph (50 km/h). Nevertheless, you
should only manually lock the differential if
absolutely necessary because engaged
locks will restrict the vehicle drive train
while cornering and cause the vehicle to
chatter. This could cause you to lose control
of the vehicle and cause an accident.
!The differential locks must not be engaged
manually when towing the vehicle or spinning the
wheels.
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