2007 MERCEDES-BENZ G55AMG wheel torque

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.

256 Operation
Driving instructions

Driving on embankments, slopes and
other steep inclines should only be
done straight uphill or downhill, i.e. in
the line of gravity. Maximum vehicle
climbing ability is a 80% grade which is
equivalent to a slope angle of approxi-
mately 38 degrees. Keep in mind that
the climbing ability of the vehicle
depends on terrain conditions.

Select gear range2 or1 on the auto-
matic transmission (
page 167).

Drive slowly.

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.

Check the brakes after a lengthy
downgrade drive.Traction in steep terrain
Be easy on the accelerator and watch for
continuous wheel traction when driving
uphill.
iFor maximum engine speed, see “Instru-
ment cluster” (
page 26) and see “Engine”
(
page 415).
Warning!G
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.
iThe 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
away from the front 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
provided.

308 Operation
Tires and wheels
If applicable to your vehicle’s tire confi-
guration, tires can be rotated according to
the tire manufacturer’s recommended
intervals in the tire manufacturer’s
warranty pamphlet located in your vehicle
literature portfolio. If none is available,
tires should be rotated every 3 000 to
6 000 miles (5 000 to 10 000 km), or
sooner if necessary, according to the
degree of tire wear. The same rotation
(spinning) direction must be maintained
(
page 280).
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder
wear on front tires and tread center wear
on rear tires).
Thoroughly clean the mounting face of
wheels and brake disks, i.e. the inner side
of the wheels/tires, during each rotation.
Check for and ensure proper tire inflation
pressure.For information on wheel change, see the
“Practical hints” section (page 366) and
(
page 390).
Warning!G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
97 lb-ft (130 Nm).
Only use genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.

395 Practical hints
Flat tire
1-5 Wheel bolts
Tighten the five wheel bolts evenly,
following the diagonal sequence illus-
trated (1 to 5), until all wheel bolts
are tight. Observe a tightening torque
of 96 lb-ft (130 Nm).
Disassemble the pump handle
(
page 392).
Put the pump handle and the wheel
wrench back into the vehicle tool kit.
Store the vehicle tool kit in the
designated storage compartment
(
page 366).
Press the jack piston in again and close
the lowering screw (
page 392).
Store the jack in the designated
storage compartment (
page 367).
After changing the wheel, secure the
damaged wheel on the spare wheel
carrier (
page 369). Make sure the
wheel cannot come loose.
Check the tire inflation pressure and
correct it if necessary.
Follow recommended cold tire inflation
pressures listed on the Tire and
Loading Information placard on the
driver’s door B-pillar (
page 280).
Warning!G
Have the tightening torque checked after
changing a wheel. The wheels could come
loose if they are not tightened to a torque of
96 lb-ft (130 Nm).

451 Index
Telephone* 226
Changing mobile phone cradle 228
Inserting in cradle 227
Installing a different mobile phone
cradle 228
Message in display 364
Removing from cradle 228
Telephone* tray
Armrest 216
Below armrest 216
Temperature
Setting interior temperature 185
Tires 287
Text messages
Multifunction display 340–343
Tie-down rings (cargo compartment) 209
Tightening torque (wheel bolts) 395
Tilt/sliding sunroof 195
Automatic opening 196
Closing 196, 374
Opening 196, 374
Opening fully 196
Stopping 196
TIN 306
Tire
Vehicle maximum load on 307Tire and Loading Information 281
Tire and loading terminology 304
Tire care and maintenance 278
Tire Identification Number see TIN
Tire inflation pressure
Checking 286, 288
Tire inspection 278
Tire load rating 306
Tire ply composition and material
used 306
Tire speed rating 250, 297, 306
Tire terminology 304
Tire traction 249
Tires 277, 416
Advanced Tire Pressure Monitoring
System (Advanced TPMS) 289
Advanced TPMS malfunction
telltale 335
Combination low tire pressure/TPMS
malfunction telltale, USA only 27
Direction of rotation 280
Driving instructions 248
Low tire pressure telltale 335
Messages in display 342–343,
361–362
Retreads 277Rims and tires 416
Rotating 307
Service life 278
Temperature 287, 303
Tread depth 279, 309
Wear pattern 308
Winter 309
Tongue Weight Rating see TWR
Tools 366
Total load limit 306
Tow-away alarm 30, 98
Arming 98
Disarming 98
Disarming for transport 98
Tow-away alarm system
Canceling alarm 98
Towing eye, front 404
Towing eye, rear 404
Towing the vehicle 401
Stranded vehicle 404
Towing the vehicle - various problem
scenarios 403
Traction 307

453 Index
Paintwork 316
Power washer 315
Seat belts 321
Side markers 318
Steering wheel 321
Tail lamps 318
Tar stains 315
Turn signals 318
Upholstery 322
Vehicle washing 316
Window cleaning 319
Wiper blades 319
Wood trims 322
Vehicle data recording 20
Vehicle Identification Number (VIN) 412
Vehicle jack 367
Vehicle loading terminology 304
Vehicle maximum load on the tire 307
Vehicle Recovery services, Stolen (Tele
Aid) 236
Vehicle status message memory 144
Calling up 144
Clearing 145
Vehicle tool kit 366
Vehicle washing 316
VIN (Vehicle Identification Number) 412W
Warning indicators
Rear Parking Assist 202
Warning sounds
Driver’s or passenger’s seat belt 77
Exterior lighting 65, 104, 117
Maintenance service indicator 313
Parking brake 55
Seat belt telltale 332, 333
Warranty coverage 411
Washer fluid see Windshield washer fluid
Washing the vehicle 315
Wear pattern (tires) 308
Weights and ratings 421
Wheel change
Tightening torque 395
Wheels
Tires and wheels 277
Window curtain air bags 74
Windows see Side windows
Windshield
Defogging 188
Replacing wiper blades 388
Washer fluid 275, 430
Washer system 430Windshield defroster 180
Activating 181
Deactivating 181
Windshield washer fluid 430
Message in display 365
Mixing ratio 430
Refilling 275
Wiping with 59
Windshield washer system 430
Windshield wipers 25, 58
Fast wiper speed 58
Intermittent wiping 59
Rear window wiper/washer 60
Replacing wiper blades 388
Single wipe 59
Switching on 58
Wiping with windshield washer
fluid 59
Winter driving 309
Block heater (Canada only) 310
Snow chains 310
Tires 309
Winter driving instructions 251
Winter tires 309