306 OperationDriving instructionsOff-road driving
Read this chapter carefully before you be-
gin off-road travel.
Familiarize yourself with the vehicle char-
acteristics and gear changing before you
attempt any difficult terrain off-road driv-
ing. 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:
Off-road – ABS (
page 94)
Off-road – ESP
® (page 98)
Off-road – 4-ETS (
page 99)
Start-off assist system (
page 191)
Downhill Speed Regulation (DSR)
(page 243)
Off-road driving program (
page 248)
Air suspension* (
page 249)
Warning!
G
Drive slowly in unknown terrain. This will
make it easier to recognize unexpected ob-
stacles and avoid damage to the vehicle.
To help avoid the vehicle rolling over, never
turn it around on steep inclines. If the vehi-
cle cannot complete the attempted climb,
back it down in reverse gear.
Do not drive along the side of a slope (dan-
ger of vehicle rollover). The vehicle might
otherwise rollover. If in doing so the vehicle
begins to show a tendency to roll, immedi-
ately steer into a line of gravity (straight up
or downhill).
Never let the vehicle roll backwards in idle.
You may lose control of the vehicle if you
use only the service brake.
Warning!
G
Sand, dirt, mud and other material having
friction property can cause exceptional wear
and tear as well as brake failure.
Have the brakes checked for dirt build-up
and cleaned. There is otherwise a risk that
full braking power may not be available in an
emergency.
309 Operation
Driving instructions
To help avoid the vehicle rolling over,
never turn it around on steep inclines.
If the vehicle cannot complete the at-
tempted climb, back it down in reverse
gear. Switch on the DSR (
page 245)
to help maintain a speed when driving
downhill.
Utilize the engine’s braking power
when descending a slope, observe the
engine speed (do not overrev the en-
gine). Apply the service brake as need-
ed.
Check the brakes after a lengthy down-
grade drive.Traction in steep terrain
Be easy on the accelerator and watch
for continuous wheel traction when
driving in steep terrain.
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.Driving across a hilltop
Decelerate just ahead of a hilltop (do
not select gear rangeN), to prevent the
vehicle from speeding up too much af-
ter climbing a hill.
Use the momentum of the vehicle to
drive across the hilltop.
Driving in this manner allows the vehi-
cle to maintain ground contact when
cresting hills.
iAvoid excessive engine speeds – drive
with moderate engine speeds
(max. 3 000 rpm).
Select gear range2 or1 on the auto-
matic transmission (
page 187).
310 OperationDriving instructionsDriving downhill
Select gear range1 on the automatic
transmission (
page 187).
Drive downhill observing the same
rules as driving uphill (
page 308).
On steep inclines, use the Downhill
Speed Regulation (
page 243).
Drive slowly.
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.
Utilize the engine’s braking power to
reduce vehicle speed.
If this is insufficient, apply the brake
gently. Make sure the vehicle is moving
in the line of gravity.
Check the brakes after a lengthy down-
grade drive.Driving through water
1Fording depth
Before driving through water, deter-
mine its depth.
It should not be deeper than approxi-
mately 20 inches (50 cm).
Make sure you check the water bed.
The ground surface may not be firm
which may result in deeper waters than
expected when driving the vehicle
through it.
For vehicles with level control*, raise
the ride height (
page 250) if neces-
sary.
Switch to the Off-road driving program
(page 248) before driving through
water.
Select gear range1 or2 on the
automatic transmission (
page 187).
Avoid high engine speeds.
Drive through the water slowly and at a
constant speed.
Vehicles with steel
suspension
120 in (50 cm)
Vehicles with Air
suspension package*
1
Raised level
20 in (50 cm)
311 Operation
Driving instructions
Switch off the exterior lamps as well as
the automatic climate control.
Enter the water only at a shallow spot,
driving at walking speed.
Do not stop vehicle while immersed in
water, and do not shut off the engine.
There is a very high level of driving re-
sistance in water. The surface is slip-
pery and may not be firm, making
pulling away in water difficult and dan-
gerous.
Clean mud off the tire tread after driv-
ing through water.
To dry the brakes, apply pressure to the
brake pedal several times after leaving
the water.Crossing obstacles!Never accelerate before driving into
the water. The bow wave could force
water into the engine and auxiliary
equipment, thus damaging them.
!Obstacles can damage the vehicle
underbody or suspension components.
If possible use the assistance of a sec-
ond 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 dis-
tance away from the vehicle and posi-
tioned so that he or she cannot get hurt
in case of any unexpected vehicle
movement.
After off-road driving or crossing obsta-
cles, inspect vehicle for any damage,
especially vehicle underbody and sus-
pension components. Failure to do so
can adversely affect the vehicle’s fu-
ture performance, including increased
chance of an accident.
313 Operation
Driving instructions
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 248).
Switch off the DSR (
page 245).
Remove excessive dirt from tires,
wheels, wheel housings, and under-
body.
For instance, after driving in mud, clean
the radiator, chassis, engine, brakes,
and wheels from extreme dirt using a
strong jet of water.
Inspect vehicle underbody, oil pan,
brake hoses, etc., as well as vehicle un-
derbody for possible damage.
Check tires for possible damage, clean
all exterior lamps, and conduct a brake
test.
Check for brush or branches caught in
the underbody.
They 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.
After continued operation in mud,
sand, water or other dirty conditions
clean the brake discs, wheels, brake
pads and check and clean axle joints.
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.
316 OperationDriving instructionsAttaching a trailer
Observe maximum permitted trailer
dimensions (width and length).
Most states and all Canadian provinces
require
safety chains between your tow 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.
a separate brake system at various
trailer weights.
a break-away switch on trailers with a
separate brake system.
The switch activates the trailer brakes
in the possible event that the trailer
might separate from the tow vehicle.
Start the engine (
page 34).
Make sure the automatic transmission
is set toP.
Set the parking brake for the vehicle
(page 52).
Vehicles with ADS*: Set the vehicle
level to Highway (
page 250).
Vehicle with ADS*: Set the ADS* to
AUTO or COMFORT (
page 249).
Stop the engine (
page 34).
Attach the trailer.
!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 func-
tion properly.iThe provided vehicle electrical wiring
harness for trailer towing has a brake
signal wire (color orange) for hook-up
to a brake controller.
You should consider using a trailer
sway control system. For further infor-
mation see an authorized
Mercedes-Benz Light Truck Center.
Warning!
G
Vehicles with ADS*:
Do not lock or unlock any doors or the tail-
gate while attaching or uncoupling the trail-
er. Do not open or close any doors or the
tailgate while attaching or uncoupling the
trailer. Make sure no one operates the ADS*
switch (
page 249) or the vehicle level
control* switch (
page 252) while a trailer
is being attached or uncoupled. The vehicle
level could change, and you could injure
yourself and/or others.
317 Operation
Driving instructions
Plug in all electrical connectors.
Towing a trailer
There are many different laws, including
speed limit restrictions, having to do with
trailer towing. Make sure your rig will be le-
gal, not only for where you reside, but also
for where you will be driving. A good
source for this information can be the po-
lice or local authorities.
Note the following points, when driving
with the trailer:
In order to gain skill and an under-
standing of the vehicle’s behavior, you
should practice turning, stopping and
backing up in an area which is free from
traffic.
Before you start driving check the
trailer hitch
break-away switch
safety chains
electrical connections
lighting and tires
Adjust the mirrors to permit unobstructed
view beyond rear of trailer.
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.
Always secure items in the trailer to
prevent load shifts while driving.
When towing a trailer, check occasion-
ally to make sure the load is secure,
and that lighting and trailer brakes (if
so equipped) are functioning properly.
Take into consideration that when tow-
ing a trailer, the handling characteris-
tics are different and less stable from
those when operating the vehicle with-
out a trailer.
It is important to avoid sudden maneu-
vers.
The vehicle and trailer combination is
heavier, and therefore is limited in ac-
celeration and climbing ability, and re-
quires longer stopping distances.
It is more prone to reacting to cross
wind gusts, and requires more sensi-
tive steering input.
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.
iWhen you are towing a trailer, the vehi-
cle level always remains in the Highway
setting.
318 OperationDriving instructions
If the transmission hunts between
gears on inclines, manually shift to a
lower gear (select 4, 3, 2 or 1).
A lower gear and reduction of speed re-
duces the chance of engine overload-
ing and/or overheating.
On very steep inclines, not manageable
with automatic transmission in1,
switch on off-road driving program
(page 248).
When going down a long hill, shift into
a lower gear and use the engine’s brak-
ing effect.
Avoid riding the brakes, thus overheat-
ing the vehicle and trailer brakes.
If the engine coolant rises to an ex-
tremely high temperature (coolant tem-
perature needle approaching the red
zone) 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 hot position.
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 re-
turn to your lane.Uncoupling the trailer
Start the engine (
page 34).
Make sure the automatic transmission
is set toP.
Set the parking brake for the vehicle
(page 52) and for the trailer.
Close all doors and the tailgate.
Detach the trailer immediately after-
ward as follows:
Disconnect all electrical plug connec-
tors.
Uncouple the trailer.
!If the trailer should begin to sway, re-
duce the vehicle’s speed immediately.
In no case attempt to straighten out the
tow vehicle and trailer by increasing
the speed.