2008 MERCEDES-BENZ GL450 steering

189 Controls in detail
Automatic transmission
Automatic transmission
For more information on driving with an
automatic transmission, see “Automatic
transmission” (
page 56).
Your vehicle’s transmission adapts its gear
shifting process to your individual driving
style by continually adjusting the shift
points up or down. These shift point adjust-
ments are performed based on current
operating and driving conditions.
If the operating conditions change, the
automatic transmission reacts by
adjusting its shift program.
Gear selector lever
The gear selector lever is located on the
right of the steering column.
Gearshift pattern for automatic
transmission
PPark position
RReverse gear
NNeutral
DDrive position
iDuring the brief warm-up, transmission
upshifting is delayed. This allows the catalytic
converter (gasoline engine) or the oxidation
catalyst (diesel engine) to heat up more quickly
to operating temperature.
Warning!G
Make sure that absolutely no objects are
obstructing the pedal’s range of movement.
Keep the driver’s footwell clear of all obsta-
cles. If there are any floormats or carpets in
the footwell, make sure that the pedals still
have sufficient clearance.
During sudden driving or braking maneuvers
the objects could get caught between the
pedals. You could then no longer brake or
accelerate. This could lead to accidents and
injury.
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192 Controls in detail
Automatic transmission
Shifting from D or R to N
If you want to select neutral positionN
with the transmission being in drive
positionD or reverse gearR:
With the vehicle at a standstill, depress
the brake pedal and keep it pressed.
Step firmly on parking brake pedal
(
page 67).
Move gear selector lever up to resis-
tance point when in drive positionD or
down to resistance point when in
reverse gearR to select neutral
positionN.
Release the brake pedal.
Shifting procedure
The automatic transmission selects indi-
vidual gears automatically, depending on:

drive positionD (page 192) with gear
ranges (
page 197)

the position of the accelerator pedal
(
page 195)

the vehicle speedWith drive positionD selected, you can use
the steering wheel gearshift control
buttons (
page 198) to influence trans-
mission shifting by:

limiting the gear range

changing gears manually
Transmission positions
The current transmission position appears
in the multifunction display.
1Current transmission position
iWhen the vehicle needs to be moved with
the engine switched off and the transmission set
to neutral positionN (
page 192), do not
depress the parking brake pedal.!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.
!If the current transmission position does not
appear in the multifunction display due to a
malfunction, for example, make sure that the
automatic transmission is in the desired position
by carefully driving off with the transmission in
drive positionD.
Do not limit the gear range.
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197 Controls in detail
Automatic transmission
On uphill grades with a gradient angle of
more than 5°, the hill start assist system
maintains the pressure in the brake sys-
tem for approximately 1 second after you
have released the brake pedal. Therefore,
you can start off smoothly without the
vehicle moving immediately after releasing
the brake pedal.
The hill start assist system is inactive

when starting off on a level road or
downhill grades

with the transmission in neutral
positionN

with the parking brake set

if the ESP® has switched off due to a
malfunctionTowing a trailer
If you tow a trailer, note the following
points:

Manually shift to a lower gear range
(
page 197) if the transmission hunts
between gears on inclines.
A lower gear range and reduction of
speed reduces the chance to overload
or overheat the engine.
For more information on trailer towing, see
the “Operation” section (
page 364).
Gear ranges
With the automatic transmission in drive
positionD, you can select a gear range for
the automatic transmission to operate
within.
You can limit the gear range by pressing
the left gearshift button on the steering
wheel gearshift control, and reverse the
gear range limit by pressing the right gear-
shift button on the steering wheel gearshift
control (
page 198).The selected gear range appears in the
multifunction display.
1Current gear range
Effect
ïThe transmission shifts through
sixth gear only.
îThe transmission shifts through
fifth gear only.
éThe transmission shifts through
fourth gear only.
èThe transmission shifts through
third gear only.
With this selection you can use
the braking effect of the engine.
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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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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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255 Controls in detail
Driving systems
Driving systems
The driving systems of your vehicle are
described on the following pages:

Cruise control (page 255) and
Distronic* (
page 260), with which
the vehicle can maintain a preset
speed.

Distance warning function*
(
page 272) is only available with
Distronic*, which warns of stationary
obstacle or slower moving vehicles that
you are closing in on too quickly.

Downhill Speed Regulation (DSR)
(
page 273), which supports you
when you are driving downhill.

Off-road driving program (page 277)
(vehicles without enhanced off-road
package*), which supports you when
you are driving off-road.

Air suspension program
There are two components available.

Vehicle level control (page 279),
which controls the vehicle level.

Adaptive Damping System (ADS)*
(
page 278), which adjusts the
vehicle suspension characteristics.

Parktronic* (page 288) and rear view
camera* (
page 293), which serve as
a parking aid.
For information on the ABS, BAS, EBP,
ESP
®, and 4-ETS, see “Driving safety sys-
tems” (
page 101).
Cruise control
The cruise control automatically maintains
the speed you set for your vehicle.
The use of cruise control is recommended
for driving at a constant speed for extend-
ed periods of time. You can set or resume
cruise control at any speed above
20 mph (30 km/h).
The cruise control function is operated by
means of the cruise control lever.
The cruise control lever is the uppermost
lever on the left-hand side of the steering
column (
page 24).
iThe cruise control should not be activated
during off-road driving.
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261 Controls in detail
Driving systems
Warning!G
Distronic adaptive cruise control is no
substitute for active driving involvement. It
does not react to pedestrians or on station-
ary objects, nor does it recognize or predict
the lane curvature or the movement of
preceding vehicles.
Distronic can only apply a maximum of 20%
of the vehicle’s braking power.
It is the driver’s responsibility at all times to
be attentive to the road, weather and traffic
conditions. Additionally, the driver must
provide the steering, braking and other
driving inputs necessary to remain in control
of the vehicle.
High-frequency sources such as toll
stations, speed measuring systems etc. can
cause the Distronic system to malfunction.
Warning!G
Distronic requires familiarity with its opera-
tional characteristics. We strongly recom-
mend that you review the following
information carefully before operating the
system.
Warning!G
Distronic cannot take road and traffic condi-
tions into account. Only use Distronic if the
road, weather and traffic conditions make it
advisable to travel at a constant speed.
Warning!G
Use of Distronic can be dangerous on slip-
pery roads. Rapid changes in tire traction
can result in wheel spin and loss of control.
Distronic does not act upon adverse sight
and distance conditions. Do not use
Distronic during conditions of fog, heavy
rain, snow or sleet.
Warning!G
Distronic cannot take weather conditions
into account. Switch off Distronic or do not
switch it on if:

roads are slippery or covered with snow
or ice. The wheels could lose traction
while braking or accelerating, and the
vehicle could skid.

the sensor is dirty or visibility is
diminished due to snow, rain or fog, for
example. The distance control system
functionality could be impaired.
Always pay attention to surrounding traffic
conditions even while Distronic is switched
on. Otherwise, you may not be able to recog-
nize dangerous situations until it is too late.
This could cause an accident in which you
and others could be injured.
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