
Differential lock
General notes
i Differential locks are available only in
vehicles with the Off-Road Pro engineering
package.
Your vehicle is equipped with the following:
R A differential lock for the transfer box: this
controls the balance between the front and
rear axles.
R A differential lock for the rear axle: this
controls the balance between the wheels
and the rear axle.
Differential locks improve the vehicle's
traction. 4ETS ( Y page 67)controls the
balance between the wheels on the front axle.
Information on "Off-road driving"; see
( Y page 166).
Information about the differential and
differential locks
When the vehicle is driving around a curve,
the wheels on the outside of the curve have
to cover a greater distance and therefore
have to turn faster than the wheels on the
inside. The differential, a transmission in the
drive train, balances these different rotational
speeds out, making cornering possible.
The disadvantage of a differential: the wheels
with the least grip are driven the hardest.
Example: one wheel on a driven axle is on a
snow-covered surface and therefore has no
traction. This wheel has the most driving
force, since the differential distributes most
of the force to the wheel with the least
resistance. The wheel on the opposite side of
this axle, which is on a solid surface and could
therefore enable traction, does not have any
driving force. 4ETS eliminates this
disadvantage and ensures good steerability
by braking the spinning wheel automatically
and thereby directing more force to the wheel
that is on a solid surface and can provide
traction.
ESP ®
and 4ETS are traction systems that are
ideally suited to road driving and driving on
easily negotiable off-road terrain. The LOW
RANGE off-road gear also improves off-road
capability.
Difficult off-road conditions require additional
measures, such as locking one or more
differentials. Your vehicle has two differential
locks: one (central) differential lock for the
transfer case and one differential lock for the
rear axle. Both differential locks can be
activated using the selector wheel on the
center console. When the (central)
differential for the transfer case is locked, the
speed of the front wheels is the same as the
speed of the rear wheels. When the
differential for the rear axle is locked, both of
the rear wheels turn at the same speed,
independent of their individual torques. Note
that activating the differential locks
significantly reduces the steerability of the
vehicle.
For your safety, the safety of others and to
prevent damage to the vehicle, the
differential locks must not be activated on
paved roads. Note that the differential
function is necessary when driving on paved
roads and that the differentials must never be
locked on paved roads. Otherwise, the
vehicle can no longer be steered. The
differential locks must therefore only be
activated when driving off-road, and then only
if activating the other driving systems (4ETS,
ESP ®
and LOW RANGE off-road gear) is no
longer sufficient.
Engaging the differential locks
! Drive off slowly when the differential
locks are engaged.
Function or performance tests may only be
performed on a 2-axle dynamometer. If you
wish to operate the vehicle on such a
dynamometer, please consult an
authorized Mercedes-Benz Center
beforehand. You could otherwise damage
the drive train or the brake system.
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Automatic mode
Use automatic mode ; for all driving
situations, including driving off-road or when
fording.
In automatic mode, the differential locks are
engaged and disengaged according to driving
requirements. This guarantees sufficient
traction for most driving situations with
unrestricted vehicle steerability.
XStart the engine.
The differential locks are in automatic
mode. The indicator lamp in selector
wheel : lights up above symbol for
automatic mode ;.
Engaging manually
GWarning!
Never drive on a paved surface with the center
and rear axle differential locks manually
engaged. Ability to steer the vehicle is greatly
reduced when the differential locks are
manually engaged, increasing the risk of an
accident.
For safety reasons, the locks are
automatically released at a vehicle speed
above 31 mph (50 km/h). Nevertheless, you
should only manually lock the differential if
absolutely necessary because engaged locks
will restrict the vehicle drivetrain while
cornering and cause the vehicle to chatter.
This could cause you to lose control of the
vehicle and cause an accident.
! The differential locks must not be
activated when the vehicle is being towed
or while the wheels are spinning.
Only engage the differential locks manually if
traction in automatic mode is insufficient.
At speeds of up to 19 mph (30 km/h), you
can engage the differential locks manually.XStart the engine.XTurn selector wheel : to desired position
= or ?.
The indicator lamp in selector wheel :
lights up at the corresponding symbol.
The engaged differential appears in the
multifunction display:
AThe differential lock for the transfer case
is locked.
If you have not previously selected the off-
road menu ( Y page 213) in the on-board
computer, the message disappears after
about five seconds.
The differential locks are not controlled
automatically. The steerability of the vehicle
is restricted considerably. Drive carefully and
accelerate gently for optimum traction.
! If the differential locks are activated
manually, the wheels scuff on the road
when cornering since the rotation
difference between the wheels is no longer
balanced out.
You can switch back to automatic mode at
any time. For safety reasons, the differential
locks disengage automatically at speeds
above 31 mph (50 km/h). If you stop the
vehicle and switch off the ignition for longer
than ten seconds, the differential locks
switch back to automatic mode.
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ROn long and steep gradients that are
difficult to drive down in shift range 1,
switch to the off-road drive program.
R When driving downhill, shift to a lower gear
to utilize the engine's braking effect.
Avoid continuous brake application as this
may overheat the vehicle brakes and, if
installed, the trailer brakes.
R If the coolant temperature increases
dramatically while the air-conditioning
system is switched on, switch off the air-
conditioning system.
Coolant heat can additionally be dissipated
by opening the windows and by setting the
blower fan and the interior temperature to
maximum.
R When overtaking, pay particular attention
to the extended length of your vehicle/
trailer combination.
Due to the length of your vehicle/trailer
combination, you will have to travel an
additional distance beyond the vehicle you
are overtaking before returning to the
previous lane.
Decoupling a trailer
GWarning!
Vehicles with air suspension program: 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
switch or the vehicle level control system
when coupling/decoupling the trailer.
XMake sure that the automatic transmission
is set to position P.XApply the vehicle's parking brake.XStart the engine.XClose all doors and the tailgate.XApply the trailer's parking brake.GWarning!
Vehicles with air suspension program: As
soon as you disconnect the electrical
connection between the trailer and the
vehicle, the vehicle will lower. To help avoid
personal injury, make sure no one is near the
wheel housing or underneath the vehicle
before the electrical connection is
disconnected.
When you decouple the trailer, the vehicle is
temporarily raised because the springs are
relieved of load. Be especially careful during
this process, as you could otherwise injure
yourself and/or others. Make sure that any
persons remaining in the vehicle do not press
the switches for vehicle level control or the
ADS.
XDetach the trailer cable and decouple the
trailer.XDetach the trailer cable and decouple the
trailer.XSwitch off the engine.
Permissible trailer load and drawbar
noseweight
Weight specifications
The Gross Trailer Weight (GTW) is the
combined weight of the trailer together with
the cargo and equipment loaded on the
trailer. Permissible gross weight:
R Vehicles with 4MATIC: 7200 lb (3265 kg)
R Vehicles without 4MATIC: 4630 lb
(2100 kg)
The permissible Trailer drawbar Weight
Rating (TWR) is the maximum weight
permitted on the trailer drawbar:
R Vehicles with 4MATIC: 576 lb (261 kg) limit
for Mercedes-Benz-approved trailer
couplings
R Vehicles without 4MATIC: 370 lb (168 kg)
limit for Mercedes-Benz-approved trailer
couplings
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Driving systemsDisplay messagesPossible causes/consequences and M Solutions°
Level Selection
Not PermittedYou cannot change the vehicle level, because:
R you are exceeding the permissible speed for the selected
vehicle level.
R you are towing a trailer.
R the trailer-coupling socket is being used, e.g. for a bicycle rack.XDrive more slowly and then select the desired vehicle level again
( Y page 184).XObserve the notes on towing a trailer ( Y page 198).°
Compressor Cooling
DownYou have selected a higher vehicle level. The compressor first
needs to cool down because of frequent level changes.XDrive in a manner appropriate for the current vehicle level.XMake sure that there is sufficient ground clearance.XAllow the compressor to cool down.
When the compressor has cooled down, the display message
disappears. The vehicle then continues rising to the selected
level.°
MalfunctionLevel control is faulty.XDo not drive faster than 50 mph(80 km/h).XMake sure that there is sufficient ground clearance.XHave the vehicle checked at a qualified specialist workshop.°
Rising
Max.12 MPHThe vehicle is being adjusted to off-road level 3. The display
message informs you of the maximum speed permissible for off-
road level 3.XDo not drive faster than 12 mph(20 km/h).°
Max.12 MPHYou are driving in off-road level 3. The display message informs
you of the maximum speed permissible for off-road level 3.XDo not drive faster than 12 mph(20 km/h).Æ
Being lowered
Max.12 MPHThe vehicle is being lowered from off-road level 3 to off-road level
2. The display message informs you of the maximum speed
permissible for off-road level 3.XDo not driver faster than 12 mph(20 km/h) until off-road level
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Display messagesPossible causes/consequences and M SolutionsÆ
Reduce speed to
under 12 MPHGRisk of accident
You are exceeding the speed permissible for the selected off-road
level.
XAdjust your driving style to the altered handling characteristics.XOnly make slight steering movements and avoid fast steering
movements.XTake account of the altered handling characteristics.XDo not driver faster than 12 mph(20 km/h).8
Locking System
Inoperative
Service RequiredThe differential locks are faulty. XDo not drive faster than 50 mph (80 km/h).XHave the vehicle checked at a qualified specialist workshop.8
Diff. Lock System
Overheated - Wait
brieflyThe differential locks are too hot and have been disengaged.XDrive on carefully.XAllow the differential locks to cool down.
The differential locks reengage as soon as they have cooled
down.8
Stop vehicle,
engage parking
brakeA gearshift process has been canceled. LOW RANGE is in the
neutral position. There is no connection between the engine and
the drive wheels.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XEngage the parking brake. Do not continue driving under any
circumstances.XRepeat the gearshift process.Å
Service Required
If parked engage
pk. brakeThe LOW RANGE system is malfunctioning. XDo not drive faster than 50 mph (80 km/h).XEngage the parking brake to park.XHave the vehicle checked at a qualified specialist workshop.Å
Max. Speed 25 MPHYou have exceeded the maximum speed for the gearshift process.XDrive slower.
The gearshift process is carried out.Å
Max. Speed 40 MPHYou have exceeded the maximum speed for the gearshift process.XDrive slower.
The gearshift process is carried out.238Display messagesOn-board computer and displays
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XTighten the wheel bolts evenly in a
crosswise pattern in the sequence
indicated ( : to A). The tightening torque
must be 110 lb-ft (150 Nm) .GWarning!
Have the tightening torque checked
immediately after a wheel is changed. The
wheels could come loose if they are not
tightened to a torque of 110 lb-ft (150 Nm).
XTurn the jack back to its initial position and
store it together with the rest of the vehicle
tool kit in the cargo compartment.
Vehicles with an emergency spare wheel:
XWrap the faulty wheel in the protective film
included with the emergency spare wheel
and transport the wheel in the cargo
compartment.
or
XDepending on the size of the wheel, you
may also be able to secure the faulty wheel
in the emergency spare wheel well. In this
case, you must remove the stowage tray
from the emergency spare wheel well and
store it securely in the cargo compartment.
Further information on stowing the
collapsible spare wheel ( Y page 299).
i When you are driving with the collapsible
spare wheel mounted, the tire pressure
loss warning system or the tire pressure
monitor cannot function reliably. Only
restart the tire pressure loss warning
system/tire pressure monitor when the
defective wheel has been replaced with a
new wheel.
Vehicles with tire pressure monitor: all
mounted wheels must be equipped with
functioning sensors and the defective
wheel should no longer be in the vehicle.
MOExtended run-flat system
The MOExtended run-flat system allows you
to drive on even if there is a complete loss of
pressure in one or more tires.
The MOExtended run-flat system may only be
used in conjunction with the activated tire
pressure loss warning system or with the
activated tire pressure monitor.
The maximum permissible distance which
can be driven in run-flat mode depends on the
cargo in the vehicle. You can drive 50 miles
(80 km) if the vehicle is partially laden and
18 miles (30 km) if it is fully laden.
The maximum permissible distance which
can be driven in run-flat mode is counted from
the moment the tire pressure loss warning
appears in the multifunction display.
You must not exceed a maximum speed of
50 mph(80 km/h).GWarning!
The handling characteristics of your vehicle
deteriorate in run-flat mode, for example:
R when cornering
R when braking
R when accelerating rapidly
Adapt your driving style accordingly and avoid
sudden changes in direction and sudden
acceleration, as well as driving over obstacles
(i.e. curbs, potholes), and driving off-road.
This is particularly the case when the vehicle
is heavily laden.
The maximum permissible distance that can
be driven in run-flat mode depends to a large
extent on the loads placed on the vehicle. It
can be shorter due to high speeds, a heavy
cargo, sudden changes in direction, the road
surface condition, outside temperature, etc.,
or further if you drive carefully and
conservatively.
Do not continue to drive in run-flat mode if:
R you hear banging noises.
R the vehicle starts to shake.
R you see smoke and smell rubber.
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Directives to be observed
R Only mount tires and wheels of the same
type and make.
R Only mount tires of the correct size onto
the wheels.
R After mounting new tires, run them in at
moderate speeds for the first 60 miles
(100 km) as they only reach their full
performance after this distance.
R Do not use tires until they are excessively
worn as the tire traction on wet road
surfaces decreases significantly when the
tread depth is less than 1
/ 8 in (3 mm).
R If the vehicle is heavily laden, check the tire
pressure and adjust it if necessary.
R When parking your vehicle, make sure that
the tires do not get deformed by the curb
or other obstacles. If it is necessary to drive
over curbs, speed humps or similar
elevations, try to do so slowly and at an
obtuse angle. Otherwise, the tires,
particularly the sidewalls, can get
damaged.
Maintenance and care of wheels and
tires
Checking wheels and tires
GWarning
Regularly check the tires for damage.
Damaged tires can cause tire inflation
pressure loss. As a result, you could lose
control of your vehicle.
Worn, old tires can cause accidents. If the tire
tread is worn to minimum tread depth, or if
the tires have sustained damage, replace
them.
R Regularly check the wheels and tires of
your vehicle for damage (e.g. cuts,
punctures, tears, bulges on tires and
deformation or severe corrosion on
wheels), at least once a month, as well as
after driving off-road or on rough roads.
Damaged wheels can cause a loss of tire
pressure.
R Regularly check the tire tread depth and
the condition of the tread across the whole
width of the tire (Y page 325). If necessary,
turn the front wheels to full lock in order to
inspect the inner side of the tire surface.
R All wheels must have a valve cap to protect
the valve against dirt and moisture. Do not
install anything on the valve (such as tire
pressure monitoring systems) other than
the standard valve cap or other valve caps
approved by Mercedes-Benz for your
vehicle.
R Regularly check the pressure of all the tires
including the emergency spare wheel or the
spare wheel, particularly prior to long trips,
and correct the pressure as necessary
( Y page 326).
Service life of tires
The service life of tires depends on the
following factors amongst other things:
R driving style
R tire pressure
R mileage
Replace the tires after six years at the latest,
regardless of wear. This also applies to the
emergency spare wheel/spare wheel.
Tire tread
GWarning
Although the applicable federal motor vehicle
safety laws consider a tire to be worn when
the tread wear indicators (TWI) become
visible at approximately 1
/ 16 in (1.6 mm), we
recommend that you do not allow your tires
to wear down to that level. As tread depth
approaches 1
/ 8 in (3 mm), the adhesion
properties on a wet road are sharply reduced.
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