2010 MERCEDES-BENZ GL450 warning

We recommend that you start out with easy
off-road travel.
Special driving features for off-road
driving
The following driving features are available for
specific kind of operation:
R Off-road ABS ( Y page 63)
R Off-road ESP ®
(Y page 65)
R Off-road 4-ETS ( Y page 64)
R Hill-start assist system ( Y page 117)
R LOW RANGE mode ( Y page 120)
R Differential locks ( Y page 121)
R Downhill Speed Regulation (DSR)
( Y page 155)
R Off-road driving program (Vehicles without
enhanced off-road package) ( Y page 158)
R Air suspension program ( Y page 159)
Off-road driving rules
R Engage the off-road driving program
( Y page 158) or LOW RANGE mode
( Y page 120) before driving under off-road
conditions.
R If necessary, activate differential locks
( Y page 121).
R Make sure you select a vehicle level
( Y page 159) appropriate to the
topographical conditions. Always make
sure the vehicle has enough ground
clearance.
R Fasten items being carried as securely as
possible ( Y page 194).
R Always navigate gradients with the engine
on and with the transmission engaged in a
gear. Switch on the DSR ( Y page 155) to
help maintain a preset speed.
! Observe the following during off-road
driving:
R Keep doors, tailgate, windows, and tilt/
sliding sunroof closed whenever driving
off-road.
R Adjust vehicle speed to condition of
terrain. The more uneven, rutty and
steeper the terrain, the lower the speed
should be. Drive through water slowly at
an even speed, avoiding a bow wave.
R Be especially careful when driving in
unknown territory. It may be necessary
to get out of the vehicle and scout the
path you intend to take.
R Watch out for obstacles, such as rocks,
holes, tree stumps and ruts.
R Before driving through water, determine
its depth.
R Do not stop vehicle while immersed in
water, and do not shut off the engine.
R In sandy soil, drive at a steady speed as
allowed by conditions. This helps
overcome the vehicle rolling resistance
and reduces the likelihood of the vehicle
sinking into the ground.
R Do not initiate jumps with the vehicle. It
interrupts the forward momentum of the
vehicle.
R Always drive onto slopes with the engine
running and the vehicle in gear.
R Do not shift automatic transmission into
neutral position N.GWarning!
Do not reduce the tire inflation pressure
before driving through sand. However, if you
do so, remember to correct the tire inflation
pressure before continuing your trip. Driving
with reduced tire inflation pressure increases
the risk of losing control of the vehicle and
rolling over.
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Checklist before off-road driving
Engine oil level
RCheck the engine oil level (Y page 230).
Only with a proper oil level can the vehicle
obtain a trouble-free oil supply, even on
steep gradients.
! If the engine oil level warning lamp comes
on while driving, stop the vehicle in a safe
location or as soon at is safe to do so.
Check the engine oil level.
The engine oil level warnings should not be
ignored. Extended driving with the symbol
displayed could result in serious engine
damage that is not covered by the
Mercedes-Benz Limited Warranty.
Tires
RCheck 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 (Y page 243).
RCheck tires for possible damage and
remove foreign objects.
RReplace missing valve caps.
Rims
RDented or bent rims can cause tire inflation
pressure loss and damage the tire beads.
For this reason, check and, if necessary,
change rims before driving off-road.
Vehicle tool kit
RCheck if the jack (Y page 286) is
functional.
RAlways take the vehicle tool kit, a strong
tow rope, a shovel and a small plank (to put
under the jack on sandy soil) with you.
Driving in steep terrain
Slope angle
:Overhang angle, front;Overhang angle, rearVehicles
with air
suspension
program
:
GL 450,
GL 350
BlueTEC
:
GL
550
;
all
models
Raised level31°32°26°Highway26°27°21°Vehicles
with
enhanced
off-road
package
:
GL 450,
GL 350
BlueTEC
:
GL
550
;
all
models
Off-road
level 3
32°33°27°Off-road
level 2
31°32°26°Off-road
level 1
28°28°23°Highway26°27°21°
RComply with the warnings (Y page 262) and
rules for off-road driving (Y page 263).
RDriving on embankments, slopes and other
steep inclines should only be done straight
up or downhill, i.e. in the line of gravity.
Maximum vehicle climbing ability is a
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100% grade which is equivalent to a slope
angle of 45°. Keep in mind that the
climbing ability of the vehicle depends on
terrain conditions.
R Shift automatic transmission into gear
range 1 (Y page 118).
R Drive slowly.
R Avoid excessive engine speeds – drive with
moderate engine speeds (max. 3 000 rpm).
R Utilize the engine’s braking power when
descending a slope, observe the engine
speed (do not overrev the engine). Apply
the service brake as needed.
i For maximum engine speed, see
“Tachometer” (Y page 125) and see vehicle
specification for your vehicle
( Y page 362).
R Check the brakes after a lengthy
downgrade drive.GWarning!
Never turn the vehicle around on steep
inclines. The vehicle might roll over. If the
vehicle cannot complete the attempted climb,
back it down in reverse gear.
i The hill-start assist system supports you
when driving uphill.
For more information, see “Hill-start assist
system” ( Y page 155).
Traction in steep terrain
The maximum vehicle climbing ability is a
100% grade which is equivalent to a slope
angle of 45°. Keep in mind that the climbing
ability of the vehicle depends on terrain
conditions.
Be easy on the accelerator and watch for
continuous wheel traction when driving in
steep terrain.
i The 4-ETS helps greatly when starting out
on a steep incline when the front wheels
have then the tendency to slip due to the
weight shifting towards the rear axle.
The 4-ETS recognizes the situation and
limits the torque for the front wheels by
braking them.
Simultaneously the torque for the rear
wheels is increased.
i Vehicles with enhanced off-road package
are equipped with automatic locks for the
center and rear axle differential to improve
vehicle traction.
Driving across a hilltop
Decelerate just ahead of a hilltop (do not shift
automatic transmission into neutral position
N ), to prevent the vehicle from speeding up
too much after climbing a hill.
Use the momentum of the vehicle to drive
across the hilltop.
After climbing a hill, driving in this manner
prevents the vehicle from:
R losing ground contact when cresting hills
R losing its forward momentum
R speeding up too much after climbing the hill
Driving downhill
R Drive slowly.
R Do not drive at an angle to the incline. Steer
into the line of gravity and drive with the
front wheels pointing straight downhill.
Otherwise, the vehicle may slide sideways
off the path and roll over.
R Shift automatic transmission into gear
range 1 (Y page 118).
R On steep inclines, use the Downhill Speed
Regulation ( Y page 155).
R Utilize the engine’s braking power to
reduce vehicle speed.
If this is insufficient, apply the brakes
gently. Make sure the vehicle is moving in
the line of gravity.
R Check the brakes after a lengthy
downgrade drive.
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Crossing obstacles
! Obstacles can damage the vehicle
underbody or suspension components. If
possible use the assistance of a second
person outside the vehicle to scout the
path you intend to take and check for
adequate ground clearance when you cross
obstacles with your vehicle. The person
assisting you outside the vehicle should
always be a safe distance away from the
vehicle and positioned so that he or she
cannot get hurt in case of any unexpected
vehicle movement.
After off-road driving or crossing obstacles,
inspect vehicle for any damage, especially
vehicle underbody and suspension
components. Failure to do so can adversely
affect the vehicle’s future performance,
including increased chance of an accident.
When driving over tree stumps, big rocks and
other obstacles, observe the following rules:
RMake sure the off-road driving program
(Y page 158) or if equipped the
LOW RANGE mode (Y page 120) is
switched on.
RAvoid high engine speeds.
RShift automatic transmission into gear
range 1 (Y page 118).
RCheck the vehicle clearance before
crossing obstacles.
RCross obstacles (e.g. tree stumps or big
rocks) very slowly by aiming one of the front
wheels at the center of the obstacle, and
repeat same with the rear wheel.
! Special attention is needed when you
cross obstacles on a steep incline.
The vehicle could slide sideways as a result
of its possible slanted position which in turn
may result in the vehicle tipping or rolling
over.
Driving on sand
GWarning!
Do not reduce the tire inflation pressure
before driving through sand. However, if you
do so, remember to correct the tire inflation
pressure before continuing your trip. Driving
with reduced tire inflation pressure increases
the risk of losing control of the vehicle and
rolling over.
When driving on sand, observe the following
rules:RSet the raised level (Y page 159).
RAvoid high engine speeds.
RShift automatic transmission into a gear
range that is appropriate for the terrain.
RIn sandy soil, drive at a steady speed as
conditions permit. This helps overcome the
vehicle rolling resistance and reduce the
likelihood of the vehicle sinking into the
ground.
RDrive in tracks of other vehicles if they are
not too deep and you have sufficient
clearance.
Ruts
A number of off-road tracks or other byways
have deep ruts which can cause the
underbody to come in contact with the
ground.
RMake sure the off-road driving program
(Y page 158) or, if equipped, the
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LOW RANGE mode (Y page 120) is
switched on.
R Set the raised level ( Y page 159).
! Check that the ruts are not too deep and
your vehicle’s clearance is sufficient.
Otherwise:
R your vehicle may be damaged
R the underbody of the vehicle may come
in contact with the ground and you may
get stuck
R Avoid high engine speeds.
R Shift automatic transmission into gear
range 1 (Y page 118).
R Drive next to the ruts rather than through
them if at all possible.
R 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 driving GWarning!
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possible
damage to your vehicle has occurred, you
should turn on the hazard warning flashers,
carefully slow down, and drive with caution 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 authorized Mercedes-Benz Center or
tire dealer for repairs.
Off-road driving increases strain on the
vehicle.
We recommend that you inspect the vehicle
for possible damage after each off-road trip.
Recognizing any damage and a subsequent
timely repair reduces the chance of a possible
breakdown or accident later on.
Proceed as follows:
R Switch off the off-road driving program
( Y page 158) or the LOW RANGE mode
( Y page 120).
R Switch off the DSR ( Y page 156).
R Set the differential locks to AUTO
( Y page 122).
R Lower the vehicle back to a level suitable
for road conditions, e.g. highway/high-
speed level ( Y page 159).
R Clean all exterior lamps and check for
possible damage.
R Clean the front and rear license plate.
R Remove excessive dirt from tires, wheels,
wheel housings, and underbody.
For instance, after driving in mud, clean the
radiator, chassis, engine, brakes, and
wheels from extreme dirt using a strong jet
of water.
R Check tires for possible damage.
R Inspect vehicle underbody, oil pan, brake
hoses, etc., as well as vehicle underbody
for possible damage.
R Check for brush or branches caught in the
underbody.
! Brush or branches could increase the
possibility of a fire, as well as cut fuel and/
or brake lines, puncture rubber bellows of
the axles or drive shafts.
R After continued operation in mud, sand,
water or other dirty conditions clean the
brake discs, wheels, brake pads and check
and clean axle joints.
R Conduct a brake test.268Driving instructionsOperation
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Trailer towingGWarning!
Failure to use proper equipment and driving
technique can result in a loss of vehicle
control when towing a trailer.
Improper towing or failure to follow the
instructions in this manual can result in
vehicle damage and/or serious personal
injury. Follow the guidelines below carefully
to assure safe trailer operation.
Contact an authorized Mercedes-Benz Center
should you require an explanation of
information contained in this manual.
Trailer hitch
R Only install a trailer hitch receiver approved
for your vehicle.
For information on availability and
installation, contact an authorized
Mercedes-Benz Center.
R The bumpers on your vehicle are not
designed for use with clamp-type hitches.
Do not attach rental hitches or other
bumper-type hitches to them.
R To reduce the possibility of damage,
remove the hitch ball adapter from the
receiver when not in use.
Electrical connections
The vehicle is prewired to accept the seven-
wire harness included in the Mercedes-Benz
approved trailer hitch receiver kit.
i A four-pole conversion plug is available
from your authorized Mercedes-Benz
Center as a spare part.
For further information, contact an
authorized Mercedes-Benz Center.
Vehicle and trailer weights and ratings
The Gross Trailer Weight (GTW) is the weight
of the trailer plus the weight of all cargo,
equipment, luggage, etc. loaded on the
trailer. The maximum permissible GTW to be
towed: 7 500 lb (3 402 kg).
Trailer Tongue Weight Rating (TWR) is the
maximum permissible weight on the trailer
tongue: 600 lb (272 kg) limit for Mercedes-
Benz approved hitch receiver.
Loading a trailer
R When loading a trailer, you should observe
that neither the permissible GTW, nor the
Gross Vehicle Weight Rating (GVWR) are
exceeded. The GVWR is indicated on the
certification label located on the driver’s
door B-pillar ( Y page 242).
Maximum permissible values are listed on
the safety compliance certification labels
for the vehicle and for the trailer to be
towed.
The lowest value listed must be selected
when determining how the vehicle and
trailer are loaded.
R The tongue weight at the hitch ball must be
added to the rear axle weight to prevent
exceeding the rear Gross Axle Weight
Rating (GAWR). The GAWR is indicated on
the certification label located on the
driver’s door B-pillar ( Y page 242).
i Mercedes-Benz recommends loading the
trailer in such a manner that it has a tongue
weight between 8 % and 15 % of the GTW.
i The weight of other accessories,
passengers and cargo will reduce the
maximum trailer weight and tongue weight
your vehicle can tow.
Checking weights of vehicle and trailer
R To assure that the towing vehicle and trailer
are in compliance with the maximum
permissible weight limits, have the loaded
rig (towing vehicle including driver,
passengers and cargo, trailer fully loaded)
weighed on a commercial scale.
R Check the vehicle’s front and rear gross
axle weight, the Gross Trailer Weight (GTW)
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The values as measured must not exceed
the weight limits listed under “Vehicle and
trailer weights and ratings” ( Y page 269).
Coupling a trailer GWarning!
While you are coupling or decoupling a trailer,
make sure nobody locks or unlocks the
vehicle and/or opens or closes doors or the
tailgate.
The vehicle’s level could change and you
could endanger yourself and/or others as a
result.
Make sure that you do not operate the ADS
button or the vehicle level control system
when coupling/decoupling the trailer.
Observe maximum permitted trailer
dimensions (width and length).
Most states and all Canadian provinces
require
R safety chains between the towing vehicle
and the trailer
The chains should be criss-crossed under
the trailer tongue. They must be attached
to the hitch receiver, and not to the
vehicle’s bumper or axle.
Make sure to leave enough slack in the
chains to permit turning corners.
R a separate brake system at various trailer
weights
R a break-away switch on trailers with a
separate brake system.
Check with your local state laws for specific
requirements.
The switch activates the trailer brakes in
the possible event that the trailer might
separate from the tow vehicle.
! Do not connect a trailer brake system (if
trailer is so equipped) directly to the
vehicle’s hydraulic brake system, as your
vehicle is equipped with antilock brakes. If
you do, neither the vehicle’s brakes nor the
trailer’s brakes will function properly.
i The provided vehicle electrical wiring
harness for trailer towing has a brake signal
wire for hook-up to a brake controller.XMake sure the automatic transmission is in
park position P (Y page 115).XEngage the parking brake for the vehicle
( Y page 112).XStart the engine ( Y page 108).XSelect the highway level ( Y page 159).XVehicles with Adaptive Damping System
(ADS):
Set the ADS to AUTO or COMF
( Y page 159).XTurn off the engine ( Y page 113).XClose all doors and the tailgate.XAttach the trailer.XPlug in all electrical connectors.
i
When you are towing a trailer, the vehicle
level always remains in the highway setting.
The following applies additionally when
towing a trailer:
R The vehicle is lowered to the highway
level when it reaches a speed of 5 mph
(8 km/h) if not set to highway level.
R The highspeed level is not available.
The restrictions that apply to towing also
apply when using accessories that are
connected to the trailer power socket, such
as a bicycle rack.
Towing a trailer
There are many different laws, including
speed limit restrictions, having to do with
trailer towing. Make sure your rig will be legal,
not only for where you reside, but also for
where you will be driving. A good source for
this information can be the police or local
authorities.
Note the following, when driving with a trailer:
R In order to gain skill and an understanding
of the vehicle’s behavior, you should
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practice turning, stopping and backing up
in an area which is free of traffic.
R Before you start driving check the
- trailer hitch
- break-away switch
- safety chains
- electrical connections
- lighting
- tires
R Adjust the mirrors ( Y page 94) to permit
unobstructed view beyond rear of trailer.
R If the trailer has electric brakes, start your
vehicle and trailer moving slowly, and then
apply only the trailer brake controller by
hand to make sure the brakes are working
properly.
R Always secure items in the trailer to
prevent load shifts while driving.
R When towing a trailer, check occasionally
to make sure the load is secure, and that
trailer lighting and brakes (if so equipped)
are functioning properly.
R Take into consideration that when towing a
trailer, the handling characteristics are
different and less stable from those when
operating the vehicle without a trailer.
It is important to avoid sudden maneuvers.
R The vehicle and trailer combination is
heavier, and therefore limited in
acceleration and climbing ability, and has a
larger braking distance.
It is more prone to reacting to cross wind
gusts, and requires more sensitive steering
input.
R If possible, do not brake abruptly, but
rather engage the brake slightly at first to
permit the trailer to activate its brake. Then
increase the braking force.
! If the trailer should begin to sway, reduce
the vehicle’s speed immediately.Do not attempt to straighten out the tow
vehicle and trailer by increasing the speed.
R If the transmission shifts between gears on
inclines repeatedly, shift to a lower gear
range manually ( Y page 118). Select 4, 3 ,
2 or 1.
A lower gear and reduction of speed
reduces the chance of engine overloading
and/or overheating.
R On very steep inclines, not manageable
with automatic transmission in gear range
1 , switch on off-road driving program
( Y page 158) or LOW RANGE mode
( Y page 120).
R When going down an incline, shift into a
lower gear and use the engine’s braking
effect.
Avoid riding the brakes, thus overheating
the vehicle and trailer brakes (if so
equipped).
R If the engine coolant rises to an extremely
high temperature when the air conditioning
is on, turn off the air conditioning system.
Engine coolant heat can be additionally
vented by opening the windows, switching
the climate control fan speed to high and
setting the temperature control to the
maximum.
R During a passing maneuver extreme care
must be exercised since your vehicle with
a trailer will require additional passing
distance ahead than when driving without
a trailer.
Because your vehicle and trailer is longer
than your vehicle alone, you will also need
to go much farther ahead of the passed
vehicle before you can return to your lane.
Decoupling a trailer GWarning!
While you are coupling or decoupling a trailer,
make sure nobody locks or unlocks the
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