W T E C I I I E L E C T R O N I C C O N T R O L S T R O U B L E S H O O T I N G M A N U A L
The World Transmission Electronic Controls (WTEC III) system features closed-loop clutch control to provide
superior shift quality over a wide range of operating conditions. MD 3000, HD 4000, and B Series configurations
can be programmed to have up to six forward ranges, neutral, and one reverse range. The MD 3070 and HD4070
have up to seven forward ranges and one reverse range.
Figure 11 is a block diagram of the basic system inputs and outputs.
Figure 11. Electronic Control Unit Block Diagram
Figure 12 shows WTEC III electronic control components.
WTEC III Electronic Controls consist of the following elements:
Remote 12/24V Max Feature Sealed Electronic Control Unit (ECU)
Remote Pushbutton or Lever Shift Selector
Optional Secondary Shift Selector
Throttle Position Sensor (TPS) (or electronic engine throttle data or PWM signal)
Engine, Turbine, and Output Speed Sensors
Control Module (Electro-Hydraulic Valve Body)
Vehicle Interface Module (VIM)
Optional Retarder Controls
Optional Engine Coolant Temperature Input
All external harnesses are OEM supplied
Some OEMs may supply their own shift selector
The VIM is an OEM option
SECTION 1 GENERAL DESCRIPTION