2008 MERCEDES-BENZ GL450 tires

207 Controls in detail
Differential locks*
Start the engine (page 42).
To select the required locking mode,
rotate adjustment ring2 to the
desired position3 or4
(
page 205).
The indicator lamp on the adjustment
ring1 at the respective symbol
comes on.
Example illustration
5Center differential is completely locked
!If the differential locks have been manually
engaged, the tires will scuff on the road surface
when cornering because the differences be-
tween the individual wheel rotation speeds will
not be compensated for.
iThe differential locks are reset to AUTO
mode after the ignition has been switched off for
longer than 10 seconds.
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345 Operation
The first 1000 miles (1500 km)
Driving instructions
At the gas station
Engine compartment
Tires and wheels
Winter driving
Maintenance
Vehicle care
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347 Operation
Driving instructions
Driving instructions
Drive sensibly – save fuel
Fuel consumption, to a great extent,
depends on driving habits and operating
conditions.
To save fuel you should:

Keep tires at the recommended infla-
tion pressures.

Remove unnecessary loads.

Remove carriers* when not in use.

Remove the crossbars* when not in
use.

Allow engine to warm up under low
load use.

Avoid frequent acceleration and decel-
eration.

Have all maintenance work performed
at the intervals specified in the
Maintenance Booklet and as required
by the Maintenance System. Contact
an authorized Mercedes-Benz Light
Truck Center.Fuel consumption is also increased by
driving in cold weather, in stop-and-go traf-
fic, on short trips and in hilly areas.
Drinking and driving
Pedals
Warning!G
Drinking and driving and/or taking drugs
and driving are a very dangerous combina-
tion. Even a small amount of alcohol or
drugs can affect your reflexes, perceptions
and judgment.
The possibility of a serious or even fatal
accident are greatly increased when you
drink or take drugs and drive.
Do not drink or take drugs and drive or allow
anyone to drive who has been drinking or
taking drugs.
Warning!G
Make sure that absolutely no objects are ob-
structing 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 maneu-
vers, 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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351 Operation
Driving instructions
Tires
Treadwear indicators (TWI) are required by
law. These indicators are located in six
places on the tread circumference and
become visible at a tread depth of
approximately
1/16in (1.6 mm), at which
point the tire is considered worn and
should be replaced.The treadwear indicator appears as a solid
band across the tread.
Specified tire inflation pressures must be
maintained. This applies particularly if the
tires are subjected to high loads (e.g. high
speeds, heavy loads, high ambient temper-
atures).

Turn the SmartKey or the SmartKey with
KEYLESS-GO* to starter switch
position0 and remove, or press
KEYLESS-GO* start/stop button (vehi-
cles with KEYLESS-GO*).

Take the SmartKey or the SmartKey with
KEYLESS-GO* with you and lock vehicle
when leaving.
Warning!G
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possi-
ble damage to your vehicle has occurred,
you should turn on the hazard warning flash-
ers, carefully slow down, and drive with cau-
tion to an area which is a safe distance from
the road.
Inspect the tires and the vehicle underbody
for possible damage. If the vehicle or tires
appear unsafe, have the vehicle towed to
the nearest Mercedes-Benz Light Truck
Center or tire dealer for repairs.
Warning!G
Although the applicable federal motor
vehicle safety laws consider a tire to be
worn when the treadwear indicators (TWI)
become visible at approximately
1/16in
(1.6 mm), we recommend that you do not
allow your tires to wear down to that level.
As tread depth approaches
1/8in (3 mm),
the adhesion properties on a wet road are
sharply reduced.
Depending upon the weather and/or road
surface (conditions), the tire traction varies
widely.
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352 Operation
Driving instructions
For more information, see “Tires and
wheels” (
page 384).
Hydroplaning
Depending on the depth of the water layer
on the road, hydroplaning may occur, even
at low speeds and with new tires. Reduce
vehicle speed, avoid track grooves in the
road and apply brakes cautiously in the
rain.
Tire traction
The safe speed on a wet, snow covered or
icy road is always lower than on a dry road.
You should pay particular attention to the
condition of the road whenever the outside
temperatures are close to the freezing
point.Mercedes-Benz recommends winter tires
(
page 420) with a minimum tread depth
of approximately 1/6in (4 mm) on all four
wheels for the winter season to make sure
normal balanced handling characteristics.
On packed snow, they can reduce your
stopping distance compared to summer
tires.
Stopping distance, however, is still consid-
erably greater than when the road is not
covered with snow or ice. Exercise appro-
priate caution.
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle. Continued
driving with a flat tire or driving at high
speed with a flat tire will cause excessive
heat build-up and possibly a fire.
Warning!G
If ice has formed on the road, tire traction
will be substantially reduced. Under such
weather conditions, drive, steer and brake
with extreme caution.
!Avoid spinning of a drive wheel. This may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited
Warranty.
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353 Operation
Driving instructions
Tire speed rating
Regardless of the tire speed rating, local
speed limits should be obeyed. Use
prudent driving speeds appropriate to pre-
vailing conditions.
An electronic speed limiter prevents your
vehicle from exceeding a speed of
130 mph (210 km/h).The factory equipped tires on your vehicle
may have a tire speed rating above the
maximum speed permitted by the
electronic speed limiter.
Make sure your tires have the required tire
speed rating as specified for your vehicle in
the “Technical data” section (
page 555),
for example when purchasing new tires.
For information on how to identify the tire
speed rating on a tire’s sidewall, see “Tire
size designation, load and speed rating”
(
page 406).
If you are uncertain about the correct
reading of the information given on a tire’s
sidewall, any authorized Mercedes-Benz
Light Truck Center will be glad to assist
you.
Winter driving instructions
The most important rule for slippery or icy
roads is to drive sensibly and to avoid
abrupt acceleration, braking and steering
maneuvers. Do not use the cruise control
system under such conditions.
When the vehicle is in danger of skidding,
shift the automatic transmission to
positionN. Try to keep the vehicle under
control by corrective steering action.
Warning!G
Even when permitted by law, never operate
a vehicle at speeds greater than the maxi-
mum speed rating of the tires.
Exceeding the maximum speed for which
tires are rated can lead to sudden tire
failure, causing loss of vehicle control and
possibly resulting in an accident and/or
serious injury and possible death, for you
and for others.
iFor information on speed ratings for winter
tires, see “Winter tires” (
page 420).
For additional general information on tire speed
markings on the tire sidewall, see “Tire speed
rating” (
page 418).
iFor information on driving with snow chains,
see “Snow chains” (
page 421).
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358 Operation
Driving instructions
Tires

Check the tread depth and maintain
specified tire inflation pressure
(a placard with the recommended tire
inflation pressures is located on the
driver’s door B-pillar (
page 388)).

Check tires for possible damage and
remove foreign objects.

Replace missing valve caps.
Rims

Dented or bent rims can cause tire in-
flation pressure loss and damage the
tire beads. For this reason, check and,
if necessary, change rims before driv-
ing off-road.
Vehicle tool kit

Check if the vehicle jack (page 492)
is functional.

In all cases take the vehicle tool kit, a
strong tow rope, a shovel and a small
plank (to put under the vehicle jack on
sandy soil) with you.Driving in steep terrain
Slope angle
1 Overhang angle, front
2Overhang angle, rear

Comply with the warnings
(
page 355) and rules for off-road
driving (
page 356).

Driving on embankments, slopes and
other steep inclines should only be
done straight up or downhill, i.e. in the
line of gravity. Maximum vehicle climb-
ing ability is a 100% grade which is
equivalent to a slope angle of
45 degrees. Keep in mind that the
climbing ability of the vehicle depends
on terrain conditions.
Vehicles with air sus-
pension program12
Raised level34°28°
Highway29°23°
Vehicles with
enhanced off-road
package*12
Off-road-level 336°30°
Off-road-level 234°28°
Off-road-level 131°25°
Highway29°23°
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363 Operation
Driving instructions

Avoid high engine speeds.

Shift automatic transmission to
position1 (
page 197).

Drive next to the ruts rather than
through them if at all possible.

If the ruts are too deep to drive in, drive
with one side of the vehicle on the
grassy center strip if the route permits.Returning from off-road drivingOff-road driving increases strain on the
vehicle.
We recommend that you inspect the vehi-
cle for possible damage after each off-road
trip. Recognizing any damage and a subse-
quent timely repair reduces the chance of
a possible breakdown or accident later on.
Proceed as follows:

Switch off the off-road driving program
(
page 278) or the LOW RANGE
mode* (
page 201).

Switch off the DSR (page 274).

Set the differential locks* to AUTO
(
page 205).

Lower the vehicle back to a level
suitable for road conditions, e.g. High-
way/High-speed level (
page 279).

Clean all exterior lamps and check for
possible damage.
!Check that the ruts are not too deep and
your vehicle’s clearance is sufficient. Otherwise:

your vehicle may be damaged

the underbody of the vehicle may come in
contact with the ground and you may get
stuck
Warning!G
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possi-
ble damage to your vehicle has occurred,
you should turn on the hazard warning flash-
ers, carefully slow down, and drive with cau-
tion to an area which is a safe distance from
the roadway.
Inspect the tires and under the vehicle for
possible damage. If the vehicle or tires ap-
pear unsafe, have it towed to the nearest
Mercedes-Benz Light Truck Center or tire
dealer for repairs.
Damage to the vehicle may influence driving
comfort and pose the risk of accident to you
and other drivers.
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