2007 MERCEDES-BENZ G55AMG Owner's Manual

168 Controls in detail
Automatic transmission
One-touch gearshifting
With the gear selector lever in drive
positionD, you can limit or extend the gear
range.Limiting gear range
Briefly press the gear selector lever to
the left in the D–direction.
The transmission will shift to the next
lower gear as permitted by the shift
program. This action simultaneously
limits the gear range of the transmis-
sion (
page 167).Extending gear range
Briefly press the gear selector lever to
the right in the D+direction.
The transmission will shift to the next
higher gear as permitted by the shift
program. This action simultaneously
extends the gear range of the transmis-
sion.
!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.
Warning!G
On slippery road surfaces, never downshift
in order to obtain braking action. This could
result in drive wheel slip and reduced
vehicle control. Your vehicle’s ABS will not
prevent this type of loss of control.
iTo avoid overrevving the engine when down-
shifting, the transmission will not shift to a lower
gear if the engine’s max. speed would be
exceeded.
iIf you press on the accelerator when the en-
gine has reached its rpm limit, the transmission
will upshift beyond any gear range limit selected.

169 Controls in detail
Automatic transmission
Canceling gear range limit
Press and hold the gear selector lever
in the D+direction until
Dreappears in
the multifunction display (
page 164).
The transmission will shift from the
current gear range directly to gear
rangeD.
Shifting into optimal gear range
Press and hold the gear selector lever
in the D-direction.
The transmission will automatically
select the gear range suited for optimal
acceleration and deceleration. This will
involve shifting down one or more
gears.Emergency operation
(Limp-Home Mode)
If vehicle acceleration becomes less
responsive or sluggish or the transmission
no longer shifts, the transmission is most
likely operating in limp-home (emergency
operation) mode. In this mode only second
gear and reverse gear can be selected.
Stop the vehicle in a safe location.
Move the gear selector lever to park
positionP.
Turn off the engine.
Wait at least 10 seconds before
restarting.
Restart the engine.
Move the gear selector lever to
positionD (for second gear) or
positionR.
Have the transmission checked at an
authorized Mercedes-Benz Light Truck
Center as soon as possible.

170 Controls in detail
Transfer case
For more information on off-road driving,
see “Off-road driving” (
page 253).
Transfer case position
Switching transfer case
The transfer case switch is located on the
lower part of the center console.
Transfer case switch
The current gear position of the transfer
case appears in the multifunction display.
1Transfer case indicator
HHIGH
Road position
LLOW
Off-road position
This position is intended for driv-
ing off-road and step gradients.
The transmission will not upshift
automatically to the next higher
gear range when driving at the
rpm limit.
The transfer case supports the
engine’s driving force
(approximately
1/2 speed).
Output is therefore increased.
NNeutral
No power is transmitted from the
engine to the drive axle.

171 Controls in detail
Transfer case
Switching from HIGH to LOW
Press upper half (“LOW”) of the
transfer case switch.
Once the shift is complete, gear
position
L appears in the transfer case
indicator1 (
page 170).
Move the gear selector lever to drive
positionD.Switching from LOW to HIGH
Press lower half (“HIGH”) of the
transfer case switch.
Once the shift is complete, gear
position
H appears in the transfer case
indicator1 (
page 170).
Move the gear selector lever to drive
positionD.
Warning!G
Always wait until the procedure of shifting
from HIGH to LOW – and from LOW to HIGH
– has been entirely completed. During this
procedure do not:

switch off the engine

shift the automatic transmission into
another gear
If you do not wait until the shifting proce-
dure has been entirely completed then it
might not be correctly performed. The
transfer case might be in neutral, thus inter-
rupting the transfer of power between the
engine and the drive axle.
The vehicle is then freely movable, even if a
gear has been selected, and could uninten-
tionally be set into motion – particularly on
up – or downhill grades. This could lead to
an accident and cause injury to yourself and
others.
Please observe related messages appearing
in the multifunction display (
page 172).
!The shift procedure can only be performed
when:

the engine is running

the gear selector lever for the automatic
transmission is in neutral positionN

the vehicle is not at standstill

the vehicle speed does not exceed 25 mph
(40 km/h)
iIf the shift procedure does not take place
press upper half (“LOW”) of the transfer case
switch once more.
!The shift procedure can only be performed
when:

the engine is running

the gear selector lever for the automatic
transmission is in neutral positionN

the vehicle is not at standstill

the vehicle speed does not exceed 40 mph
(70 km/h)
iIf the shift procedure does not take place
press lower half (“HIGH”) of the transfer case
switch once more.

172 Controls in detail
Transfer case
Messages in the multifunction display
If a shift was not completed and one of the
following messages appears in the multi-
function display:

TC shift conditions not fulfilled
The shift did not take place. At least
one shift condition was not met.
Repeat the shift procedure.

TC in neutral
The shift did not take place. The
transfer case is in neutral. Gear
position
N appears in transfer case
indicator1.
Repeat the shift procedure.

TC shift procedure canceled
The shift did not take place.
Repeat the shift procedure.

Transfer case Visit workshop
There may be a malfunction in the
system.
Repeat the shift procedure.
If the shift procedure still does not take
place, have the vehicle checked at an
authorized Mercedes-Benz Light Truck
Center as soon as possible.For more information, see “Practical hints”
section (
page 363).
Warning!G
If the transfer case is in neutral, transmis-
sion positionP will not hold vehicle. The
parking brake must be applied to hold
vehicle in place.
iIf the SmartKey is in starter switch
position0 or1, an alarm will sound if the
transfer case is in neutral and the driver’s door is
opened.
Engage the transfer case to gear positionHIGH
orLOW.

173 Controls in detail
Differential locks
Differential locks
For more information on off-road driving,
see “Off-road driving” (
page 253).
Differential locks improve the vehicle’s
tractive power off-road. Switch on
differential locks:

for off-road driving

to turn the ABS off during off-road
driving

for driving through water

when driving on deep snow and icy or
fouled surfaces
!Do not engage the front axle differential
lock when driving around tight corners. This
restricts steering ability.
!When driving off-road, apply only moderate
pressure to the accelerator pedal if the differen-
tial locks are switched on.
When running on a (single-axle) dynamometer –
no matter how briefly – you must:

raise the non-driven axle
or

disconnect its drive shaft
and

engage the transfer differential lock
Otherwise the transfer case can be damaged,
which is not covered by the Mercedes-Benz
Limited Warranty.
Warning!G
Never drive on pavement with differential
locks engaged.
Steering control will be strongly affected
with the differential locks activated.
The ABS, BAS, and ESP
® are switched off
automatically when the transfer case
differential lock is activated.

174 Controls in detail
Differential locks
A few words about differentials and
differential locks
When a vehicle negotiates a turn, wheels
on the outside of the curve must travel
farther 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
possible.
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
engine’s power will go to that wheel
because the power will take the path of
least resistance. Meanwhile, the opposite
wheel, sitting 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 (4-ETS)
addresses 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 4-ETS in this vehicle
feature such intelligent limited-slip
differential technology, ideally suited for
on-road and light off-road driving. Transfer
case position LOW (
page 170) also
enhances off-road driving capabilities
(
page 253).
More extreme off-road conditions may call
for another solution, engaging a differen-
tial lock or preventing the differential from
operating altogether. As part of its stan-
dard equipment, this vehicle comes with
three differential locks: front, transfer case
(center) and rear. Each can be engaged
simply by pushing dashboard-mounted
switches in sequential order (center, rear,
front) (
page 175). When the transfer
case (center) differential is locked, half of
the engine’s power is automatically
distributed to the front wheels and half to the rear wheels. When the rear differential
is locked, power going to the rear wheels is
equally distributed, so that both rear
wheels turn at the same speed and torque.
When the front differential is locked, all
four wheels now turn with equal power and
torque. Please be aware that engaging 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
important to understand that during
on-road/paved driving, differentials are
absolutely necessary for providing the
essential 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®,
manual switch position “LOW” of transfer
case) this vehicle comes equipped with.

175 Controls in detail
Differential locks
Switching differential locks on and off
The switches are located on the upper part
of the center console.
1Transfer case (center) differential lock
2Rear axle differential lock
3Front differential lock
4Engagement indicator lamps (yellow)
5Function indicator lamps (red)Switching differential locks on
Transfer case differential lock
Press switch1.
The yellow engagement indicator
lamp4 for the transfer case
differential lock comes on.
The ESP
® warning lampv comes
on.When the differential lock engagement
operation has been completed, the red
function indicator lamp5 comes on.
The message
ABS not available
differential locked
appears in the
multifunction display.
The ESP
® warning lampv and
the- indicator lamp in the
instrument cluster come on.
Once the transfer case differential lock
is switched on, you can now, if needed,

switch on rear axle differential
lock2
or

switch on rear axle differential
lock2 and front differential
lock3.
iThe differential locks can only be switched
on in the sequence1, 2, 3.
!To avoid damage to the transfer case and
differential locks:

Engage differential locks only at low speed
(walking speed, not more than 5 mph
[8 km/h]).

Do not engage differential locks if the driving
wheels are spinning due to lack of traction.

Do not engage differential locks on paved
roads.