A shift in Four Wheel Driving
The traditional Four Wheel Drive is changing in capability, operating and driving dynamics. The
traditional lever operated Low Range transfer case is becoming history. The manual transmission
and locking hubs is also history.
So what has changed? What does it mean to the four wheel driving enthusiast? The table below
gives an appreciation of ‘the old and new vehicle’ components.
Traditional components and systems
Ladder Frame chassis
Fixed beam axles
Low Range Transfer Case
Modern components and systems
Terrain Response System
Hill Descent Control
Traction Control
Torque Vectoring
Suspension Control
Crawl Control
Electronic Differential Locking
Terrain Sensors
In the traditional systems, the driver can select Four Wheel Drive High/Low range when going off
road. This enables to control the torque output, but the rest depends on the driver to gain traction
for the terrain. These systems are heavily dependent on getting momentum and taking the correct
line when tackling off road terrain.
The moderns systems present the driver with a series of settings, so knowing the terrain and
optimally configuring the vehicle is the most needed skill. It is not just selecting a setting from a dial
and/or screen. The driver must have the knowledge of each setting in advance to adjust to a suitable
driving style. Consider the table below which shows the settings for a typical terrain response system
in a modern vehicle.
Selection Mode
Normal/General
Land Rover (Terrain
Response 2) *
Maximises Fuel
efficiency, minimises
emissions
Grass/Show/Gravel Traction control
reduces tyre slip, gears
change quickly,
throttle response
softened, Hill Descent
Control (HDC) engages
when required.
Sand
Heightens engine and
gearbox response and
locks the centre
differential.
Mitsubishi Pajero
Sport(Off Road
Mode)*
Sets vehicle to ‘on
road’ dynamics
Optimises wheel slip
and stability
Maintains high RPM
to maximize torque,
quickens gear shifts
Ford Everest (Terrain
response Management) *
Full time 4WD with torque
management over front
and rear axles.
Throttle is less sensitive,
gears shift up earlier and
shift down later, Torque is
transferred between the
front and rear axles when
required.
Throttle is more sensitive,
delays up/down gear
shifts, traction control
allows wheels to spin,
engine maintains high
Revolutions Per
Minute(RPM)