Inputs for the Chassis ECM that are Used by the Transmission ECM
The following inputs to the Chassis ECM are also used by the Transmission ECM:
- Shift lever switch (2)
- Hoist position sensor (3)
- Dump body position sensor (5)
Shift Lever Switch
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| Illustration 1 | g01905656 |
(1) Shift lever (2) Shift lever switch | |
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| Illustration 2 | g00466290 |
View of shift lever switch | |
The shift lever switch (2) is mechanically positioned with diodes that determine the current flow. The shift lever switch (2) provides the Chassis Electronic Control Module (Chassis ECM) with information about the position of the shift lever (1). The Chassis ECM then sends this information to the Transmission Electronic Control Module (Transmission ECM). The Transmission ECM uses this information in order to determine the correct speed for the transmission. Shift lever switch (2) is mechanically connected to shift lever (1) inside the shift console.
Manual Shifting
In the manual shifting mode, the Transmission ECM shifts the transmission based upon the operators selection on shift lever (1). Manual operation includes REVERSE, NEUTRAL, and FIRST gears. The maximum forward gear is also the minimum automatic gear.
Automatic Shifting
The Transmission ECM provides fully automatic shifting from the minimum automatic gear to the top gear limit.
In the automatic shifting mode, the operator sets shift lever (1) to the maximum gear range that is desired. All of the automatic upshifts and the automatic downshifts are dependent on the speed of the machine. The automatic upshifts and automatic downshifts are preprogrammed in the Transmission ECM for each gear. The shift points are raised slightly by the use of the retarder or by the service brakes. Usually, there will not be any additional upshifts that will occur after the transmission reaches the the gear range that is selected by the operator. During normal shifting, the Transmission ECM does not allow a turnaround shift until approximately 4.5 seconds after a shift occurs. This delay allows mechanical conditions to stabilize before an opposite shift occurs. This delay also allows hydraulic conditions to stabilize before an opposite shift occurs. This delayed turnaround feature is commonly referred to as Anti-Hunt. Inputs from the service/retarder brake and from the parking and secondary brake eliminate this feature.
Hoist Position Sensor
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| Illustration 3 | g01905657 |
View of hoist control (3) Hoist control position sensor | |
The hoist control is located to the left of the operator's seat. The hoist control is connected to the hoist control position sensor (3). The hoist control position sensor (3) sends electrical signals to the Chassis Electronic Control Module (Chassis ECM). See the hydraulic system System Operation, "Position Sensor (Hoist Control)" for additional information.
If the transmission control is placed in the REVERSE position and the dump body is being raised, the position sensor for the hoist control is used to shift the transmission to the NEUTRAL position. The transmission will remain in the NEUTRAL position until the following Steps are taken:
- The hoist control is moved to the HOLD position or to the FLOAT position.
- The transmission control has been moved into the NEUTRAL position and the transmission control has been moved out of the NEUTRAL position.
Dump Body Position Sensor
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| Illustration 4 | g01905659 |
(4) Rod (5) Dump body position sensor | |
Dump body position sensor (5) is located on the frame near the left pivot pin for the dump body. Rod (4) is connected between dump body position sensor (5) and the dump body. When the dump body is raised, rod (4) rotates dump body position sensor (5), which changes the Pulse Width Modulated signal that is sent to the Chassis Electronic Control Module (Chassis ECM). The adjustment of the rod between the sensor and the dump body is very important. See the Hydraulic System Testing and Adjusting, "Position Sensor (Dump Body) - Adjust" for the proper adjustment procedure.
Dump body position sensor (5) is used in order to limit the top gear while the dump body is up. The Chassis ECM comes from the factory with the top gear value that is set to FIRST gear. The transmission will not shift past FIRST gear until the dump body is down. The top gear value is programmable by utilizing the Electronic Technician (ET). The top gear value can be changed to SECOND gear or THIRD gear.
Note: If the transmission is already above the previously set gear limit when the body goes up, no limiting action will take place.