2008 MERCEDES-BENZ GL450 Power

194 Controls in detail
Automatic transmission
If you want the gear position to remain in
neutral positionN, e.g. when taking the
vehicle through an automatic conveyor
type car wash, observe the following
instructions.Vehicles with SmartKey:
With the vehicle at a standstill and the
ignition switched on shift the automatic
transmission to neutral positionN.
If engaged, release the parking brake
(
page 59).
Switch off the ignition and leave the
SmartKey in the starter switch.
Vehicles with KEYLESS-GO*:
With the vehicle at a standstill, depress
the brake pedal and keep it pressed.
With the ignition switched on shift the
automatic transmission to park
positionP.
Release the brake pedal.
Remove the KEYLESS-GO* start/stop
button from the starter switch
(
page 43).
Effect
íReverse gear
Shift into reverse gearR only
when the vehicle is stopped.
ëNeutral
No power is transmitted from the
engine to the drive axle. When
the brakes are released, the
vehicle can be moved freely
(pushed or towed).
To avoid damage to the transmis-
sion, never shift into neutral
positionN while driving.
If the ESP
® is deactivated or
malfunctioning:
Shift into neutral positionN only
if the vehicle is in danger of
skidding, e.g. on icy roads.
!If you turn off the engine using the
SmartKey or the KEYLESS-GO* start/stop
button, the transmission will shift to neutral
positionN automatically.
Warning!G
When leaving the SmartKey or SmartKey
with KEYLESS-GO* in the starter switch, do
not leave children unattended in the vehicle.
It is possible for children to switch on the
ignition which could result in unsupervised
use of vehicle equipment.
A child’s unsupervised access to a vehicle
could result in an accident and/or serious
personal injury.
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198 Controls in detail
Automatic transmission
Steering wheel gearshift control
With drive positionD selected, you can
limit or extend the gear range.
1Left button: limiting gear range or
downshift
2Right button: extending gear range or
upshiftEffect
çThe transmission shifts through
second gear only.
Allows the use of engine’s
braking power when driving:

on steep downgrades

in mountainous regions

under extreme operating
conditions
æThe transmission operates in
first gear only.
For maximum use of engine’s
braking effect on very steep or
lengthy downgrades.
!Allow engine to warm up under low load use.
Do not place full load on the engine until the
operating temperature has been reached.
Shift into reverse gearR or park positionP only
when the vehicle is stopped.
Avoid spinning of a drive wheel for an extended
period when driving off on slippery road
surfaces. This may cause serious damage to the
drivetrain which is not covered by the
Mercedes-Benz Limited Warranty.
iYou cannot shift with the steering wheel
gearshift buttons when the transmission is in
positionP,N orR.
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201 Controls in detail
Transfer case
Transfer case
LOW RANGE mode*
The LOW RANGE mode is available on vehi-
cles with enhanced off-road package*.
In the following situations you should
switch to LOW RANGE mode:

during off-road driving (page 355)

when crossing water (page 360)

when towing up or down on steep
gradients
With the LOW RANGE selected, the
engine’s power delivery and the shifting
behavior of the automatic transmission are
adjusted. Furthermore, the ABS, ESP
® and
4-ETS functions especially adapted to
off-road travel are activated.
For information on driving safety systems
during LOW RANGE mode, see “Driving
safety systems” (
page 101).
For more information on Off-road driving,
see “Off-road driving” (
page 355).Gear Ranges
There are two possible settings.
!Operational or performance test must only
be conducted on a two-axle dynamometer. If
such tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1 or
KEYLESS-GO* start/stop button in
position0or1) when testing the parking brake
on a brake test dynamometer and such testing
should be no longer than 10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
iThe vehicle is equipped with permanent
four-wheel drive. Both the front and rear axles
are powered at all times when the vehicle is
being operated.
HIGH
RANGERoad position for all normal
driving situations.
(LOW RANGE mode off)
LOW
RANGEOff-road position for traveling
on rough terrain.
(LOW RANGE mode on)
Also use the off-road position
when driving on-road on steep
gradients, especially when
towing a trailer.
LOW RANGE acts by raising
the engine’s gear ratio. The ve-
hicle travels at roughly third
the speed compared to when
in the HIGH RANGE position,
leading to an increase in the
engine’s drive power.
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202 Controls in detail
Transfer case
Switching LOW RANGE mode
The switch is located on the upper part of
the center console.
1LOW RANGE switch
2Indicator lamp
3LOW RANGE displaySwitching LOW RANGE mode on
(switching from HIGH RANGE to LOW
RANGE)
Press LOW RANGE switch1.
Indicator lamp2 flashes.
If the system senses that all conditions
are met, it will switch to LOW RANGE
mode. A chime sounds and the LOW
RANGE display3 appears in the multi-
function display.
The indicator lamp2 on the
LOW RANGE switch comes on continu-
ously, indicating that the LOW RANGE
mode has been activated.
Warning!G
Always wait until the procedure of shifting
from HIGH RANGE to LOW RANGE – and
from LOW RANGE to HIGH RANGE – has
been entirely completed. During this proce-
dure do not:

switch off the engine

shift the automatic transmission into
another gear
If you do not wait until the shifting proce-
dure has been entirely completed then it
might not be correctly performed. The trans-
fer case might be in neutral, thus interrupt-
ing the transfer of power between the
engine and the drive axle.
The vehicle is then freely movable, even if a
gear has been selected, and could uninten-
tionally be set into motion – particularly on
up – or downhill grades. This could lead to
an accident and cause injury to yourself and
others.
Please observe related messages appearing
in the multifunction display (
page 488).
!The shift procedure can only be performed
when the following conditions are met:

The engine is running (page 41).

The automatic transmission is in positionN
(
page 190).

The vehicle speed does not exceed 25 mph
(40 km/h).
iThere is no reset to HIGH after the ignition
has been switched off.
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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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209 Controls in detail
Good visibility
Power folding exterior rear view
mirrors*
Folding the exterior rear view mirrors
in and out automatically
When the corresponding function in the
control system is activated (
page 182):

The exterior rear view mirrors automat-
ically fold in as soon as the vehicle is
locked from the outside.

The exterior rear view mirrors automat-
ically fold out as soon as the vehicle is
unlocked and the driver’s or front pas-
senger door are subsequently opened.Synchronizing exterior rear view
mirrors
The power folding rear view mirrors may
have to be synchronized after the vehicle
battery has been disconnected or dis-
charged. If the exterior rear view mirrors
do not fold properly upon locking or un-
locking the vehicle although the corre-
sponding function in the control system is
activated (
page 182), do the following:
Fold each exterior rear view mirror in
completely (
page 210).
Fold each exterior rear view mirror out
completely (
page 210).
When the exterior rear view mirrors fold
properly upon locking the vehicle, the exte-
rior mirrors are synchronized. Otherwise
repeat the above steps.
Warning!G
The auto-dimming function does not react if
incoming light is not aimed directly at sen-
sors in the interior rear view mirror.
The interior rear view mirror and the exterior
rear view mirror on the driver’s side do not
react, for example, when transporting cargo
which covers the rear window.
Light hitting the mirror(s) at certain angles
(incident light) could blind you. As a result,
you may not be able to observe traffic con-
ditions and could cause an accident.
Warning!G
Exercise care when using the passen-
ger-side exterior rear view mirror. The mirror
surface is convex (outwardly curved surface
for a wider field of view). Objects in mirror
are closer than they appear. Check your
interior rear view mirror or glance over your
shoulder before changing lanes.
!Before you drive the vehicle through an
automatic car wash, fold the exterior rear view
mirrors in. Otherwise they may get damaged.
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212 Controls in detail
Good visibility
Adjust sun visor1 by pushing or pull-
ing in the direction of arrows.
Swing down additional sun visor*2
when you experience additional glare
through the windshield.
Rear panorama roof sunshade
The rear panorama roof sunshade over the
third-row seats prevents the sun from shin-
ing directly into the vehicle.
You can open and close the sunshade by
hand.1Mounting
2Clip
3Handle
4Button
Closing
Grasp on handle3 and insert clips2
into mounting1.
The third-row sunshade engages.
Opening
Press on button4 to disengage the
third-row sunshade from mounting1.
Rear window defroster
The rear window defroster uses a large
amount of power. To keep battery drain to
a minimum, switch off the defroster as
soon as the rear window is clear. The de-
froster is automatically deactivated after
approximately 6 to 17 minutes of
operation depending on the outside tem-
perature.
Switch on the ignition (page 42).
!To avoid damage to vanity mirror cover4
(
page 211), make sure it is closed before
pivoting sun visor1 to the side.
!Always guide the sunshade. Do not let it
snap back abruptly, as it could be damaged.
Warning!G
Any accumulation of snow and ice should be
removed from the rear window before driv-
ing. Visibility could otherwise be impaired,
endangering you and others.

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221 Controls in detail
Climate control
Adjusting air distribution
Move air vent slider2 to the left, right,
up, or down to direct the air in the de-
sired direction.
Front defroster
You can use this setting to defrost the
windshield, for example if it is iced up. You
can also use it to defog the windshield and
door windows.
Activating
Press button| (page 216).
The indicator lamp on the button
comes on.The climate control switches to the follow-
ing functions automatically:

most efficient blower speed and
heating power, depending on outside
temperature

air flows onto the windshield and the
door windows (side air vents must be
open)

the air conditioning compressor
switches on at outside temperatures
above approximately 41°F (5°C) for
air-drying
Adjustments
You can adjust the air volume and the tem-
perature when the front defroster is
switched on. The air flow will remain on the
windshield and door windows.
Press button
to decrease or
buttonQ to increase air volume
(
page 216) to the desired level.The air volume decreases/increases to
the next lower/higher blower speed
and heating switches to the tempera-
ture that was set before the front de-
froster was switched on.
The indicator lamp on button|
goes out. The indicator lamp on
button9 comes on.
or
Turn temperature control1
and/or7 (
page 216) slightly in any
direction.
Heating switches to the temperature
that was set before the front defroster
was switched on.
The indicator lamp on button|
goes out. The indicator lamp on
button9 comes on.iKeep this setting selected only until the
windshield or the door windows are clear again.
iThe air conditioning compressor remains on
even if the indicator lamp in button| goes
out. This helps to prevent the windshield from
fogging.
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