SsangYong Stavic / SsangYong Rodius (2005 year). Service manual - part 349

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3

TOD

STAVIC - 2004.09

4D

GENERAL INFORMATION

1. LAYOUT

T/M

Front propeller shaft

Transfer case (TOD)

Sub frame

Exaust pipe

Rear propeller shaft

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4

TOD

STAVIC - 2004.09

4D

TOD system means the full time 4WD system and the
registered trade mark of Borg Warner. TOD is an abbre-
viation of Torque On Demand.

TOD (Torque On Demand) system, which is superior than
existing Full Time 4WD, checks the road surface and ve-
hicle conditions via various sensors and, subsequently,
according to the situations and conditions, distributes the
most optimal driving force to front wheels and rear wheels
by activating the electro-magnetic clutch located inside of
TOD Transfer Case.

TOD receives the speed signals from speed sensors in-
stalled in front axle and rear axle, the TPS signals from
engine, and the operating signals from ABS control unit
via CAN. Based on these data, TOD control unit controls
the electro-magnetic clutch to distribute the 3:97 ~ 44:56
of driving force to front wheels and rear wheels.

The conventional system uses “FR driving” (theoretically,
the 100 % of driving force is transferred to rear wheels) on
normal paved road. When the system detects a slip in the
rear wheels, a proper percentage of driving force is trans-
ferred to front wheels.

TOD control unit receives the wheel speed signals from
the speed sensors in propeller shaft of transfer case and
engine output information from the engine control unit. TOD
control unit changes the pressure force of the electro-
magnetic clutch based on the analyzed data.

Distribution of Driving Force
According to Road Surface

1. On normal road surface

In vehicle with existing part time transfer case, when
a driver turns the steering wheel to park in the 4WD
mode, the vehicle may halt sensation of tight corner
braking phenomena. However, in vehicle with TOD
system, this phenomena does not occur and the
driving force is properly and automatically distributed.

2. On paved road with high speed

Driving at high speed on roads such as highway
mainly uses rear wheels as driving wheel. At this
moment, some of torques is also distributed to front
wheels so that the vehicle could maintain safe ground
grab capacity against side winds and rain. Distribution
ratio: 15 % for front wheels and 85% for rear wheels.

3. When turning on the road with low friction rate

During cornering on roads such as unpaved, snowy,
icy and muddy, ground grab capacity is increased
by distributing required torque and, at the same time,
comfortable steering operation is maintained by
controlling the ground grab capacity at high level.
Distribution ratio: 30 % for front wheels and 70 % for
rear wheels.

4. When climbing or starting off on the road with low

friction rate

In order to secure the maximum ground grab capacity
and driving force during climbing or starting off on the
roads such as unpaved, snowy and icy road, the
system controls the driving force to distribute properly
in full 4WD mode. Distribution ratio: 44 % for front
wheels and 56 % for rear wheels.

2. GENERAL DESCRIPTION

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5

TOD

STAVIC - 2004.09

4D

Transfer Case

Planetary gear set

Planetary Gear set consists of sun gear, ring gear and carrier. It is engaged with the gear in “HIGH-LOW” collar to
increase the driving force by reducing vehicle speed.

Sun gear is connected to input shaft and ring gear is fixed into the transfer case.

Splined rear output shaft is able to slide on the “HIGH - LOW” collar.

The inside and outside ends of “HIGH - LOW” collar have machined gear. The input shaft transmits the power to driving
wheels by engaging with sun gear and carrier gear.

If the 4WD switch is at “4WD HIGH”, the TOD control unit operates the shift motor to engage “HIGH - LOW” collar
directly with input shaft for transmitting the driving force to front and rear propeller shafts.

When a driver selects “4WD LOW”, the TOD control unit controls the electro-magnetic clutch and operates the shift
motor to engage “HIGH - LOW” collar with carrier. The power from transmission is increased up to 2.48:1 by reduction
ratio from planetary gear, and then is sent to front and rear propeller shafts.

Ball type slant cam and clutch disc pack

If the speed sensors installed on front and rear propeller shafts
detect the slips at front and rear wheels, and these slips ex-
ceed the specified range, TOD control unit controls electro-
magnetic clutch to transmit driving force to front wheels. At
this time, ball slant cam is moved to compress multi-disc
located in clutch disc to transmit driving force to front wheels.

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EFFECTIVE DATE

AFFECTED VIN

6

TOD

STAVIC - 2004.09

4D

Electro Magnetic Clutch (EMC)

EMC consists of coil and housing. TOD control unit controls EMC by controlling duty cycle according to the road and
driving conditions. These controls use the continuity time and amount of electric current to determine the torque to be
transmitted to front wheels.

 Basic controls in EMC

Measuring the rotating speed

of front propeller shaft

Measuring the rotating

speed of rear propeller shaft

Is the wheel slip exceeded

allowable limits?

Increases clutch engagement

Decreases clutch engagement

NO

YES