STARTING AND STOPPING PROCEDURE
4 - 4
Engine Electronic Control Module (via direct
electronic communication), speed sensors, and
push-button shifter transmit information to the
ECU. The ECU processes this information and
sends signals to actuate specific solenoids lo-
cated on the control module in the transmission.
These solenoids control both the oncoming and
offgoing clutch pressure during a shift.
Another feature of the World Transmission is its
ability to adapt and learn as it operates. Each
shift is electronically measured, stored and used
by the ECU to adapt and learn the optimum con-
ditions for future clutch apply and release. It is
important to note that if the shift quality of low
mileage vehicles or vehicles with new or recali-
brated ECU's is unacceptable, simply drive the
vehicle through its shift ranges for awhile. After
this learning period any rough shifting will be cor-
rected and shift quality will be restored.
In addition to controlling the operation of the
transmission, the ECU monitors the system for
conditions that could result in damage to the
transmission or improper vehicle operation.
When one of these conditions is detected, the
ECU is programmed to respond automatically in
a manner which ensures safe operation of the
vehicle and the transmission.
Torque Converter
The torque converter consists of three (3) ele-
ments: pump, turbine, and stator. The pump is
the input element and is driven directly by the
engine. The turbine is the output element and is
hydraulically driven by the pump. The stator is
the reaction (torque multiplying) element. When
the pump turns faster than the turbine, the torque
converter is multiplying torque. When the turbine
approaches the speed of the pump, the stator
starts to rotate with the pump and turbine. When
this occurs, torque multiplication stops and the
torque converter functions as a fluid coupling.
The lockup clutch is located inside the torque
converter and consists of three elements: piston,
clutch plate/damper, and backplate. The lockup
clutch is engaged and released in response to
electronic signals from the ECU and provides a
direct drive from the engine to the transmission
gearing. This eliminates converter slippage to
provide maximum fuel economy. The torsional
damper absorbs engine torsional vibration.
The lockup clutch releases at lower speeds and
when ECU detects conditions requiring it to be
released.
Planetary Gear and Clutches
A series of three helical planetary gear sets and
shafts provide the gear ratios and direction of
travel for the vehicle. The planetary gear sets are
controlled by five multiplate clutches that work in
pairs to produce six speeds. The clutches are
applied and released hydraulically in response to
electronic signals from the ECU to the appropri-
ate combination of solenoids.
Cooler Circuit
The transmission oil is cooled by a remote-
mounted oil cooler. Connections to the cooling
circuit are located at the rear of the transmission
to facilitate installation of remote cooler lines. Oil
ports are internal requiring only coolant to be
routed to and from the cooler.
Transmission Retarder
(optional)
The retarder is not a brake but a device that
helps in reducing the speed of a vehicle. It en-
ables an easier control of the vehicle, a safer
driving, and a more economical operation. Re-
tarder provides slowing power when it is most
needed, such as driving down windy mountain
roads, in stop-and-go traffic, on crowded free-
ways.
The retarder system is activated by turning
ON
the retarder enable switch (4
th
from ignition on
L.H. lower control panel - see page 2-6).
The retarder controls are broken down in two
types:
BRAKE APPLY
- actuated by brake pressure;
applies the retarder at three distinct retardation
levels (low (1/3) at 2 psi, medium (2/3) at 4 psi,
and "full on" at 7 psi) when increasing pressures
are detected in the brake system.
Warning:
Always manually disable the retarder
controls (turn Off enable switch) during inclement
weather or slippery road conditions.
