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| Illustration 1 | g03404478 |
(1) Transmission direction control switch (2) Transmission upshift switch (3) Transmission downshift switch | |
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| Illustration 2 | g03404479 |
Right Side of the Cab, Overhead (4) Manual position (5) Transmission auto/manual switch | |
The power train ECM automatically shifts the transmission if the five-position auto/manual switch (5) is in one of the four AUTO positions. The power train ECM evaluates the input that is sent from the following sensors in order to regulate transmission shifts:
- engine speed sensor
- transmission speed sensors
- torque converter output speed sensor
The power train ECM does not allow automatic upshifts to a speed that is higher than the speed that is selected with the auto/manual switch. An automatic downshift from second speed to first speed occurs only if the five-position auto/manual switch (5) is in the 1-4 position.
| Automatic Upshift and Automatic Downshift (1) | |
| Speed Range and Direction Shift | Transmission Speed in RPM |
| 1F to 2F | 310 |
| 2F to 3F | 550 |
| 3F to 4F | 970 |
| 4F to 3F | 900 |
| 3F to 2F | 510 |
| 2F to 1F | 285 |
| 1R to 2R | 350 |
| 2R to 3R | 630 |
| 3R to 4R | 1110 |
| 4R to 3R | 1030 |
| 3R to 2R | 580 |
| 2R to 1R | 325 |
| ( 1 ) | The speeds that are listed are approximate. The speeds that are listed should be used for reference only. |
The operator can override the autoshift function by depressing transmission downshift switch (3). The operator must perform one of the procedures that follow in order to resume automatic upshifts. Either depress transmission upshift switch (2), or shift to a different direction of travel. Momentarily depressing transmission downshift switch (3) signals the power train ECM to downshift the transmission by one speed. Pressing and holding transmission downshift switch (3) signals the power train ECM to continue to downshift the transmission as the machine speed decreases.
When the key start switch is turned from the OFF position to the ON position, the power train ECM is activated. When the power train ECM is first activated, all the modulating valves (transmission clutch) are de-energized. The modulating valves are de-energized regardless of the position of transmission direction control switch (1). The power train ECM then determines if transmission direction control switch (1) is in the NEUTRAL position. The power train ECM disables the transmission if the NEUTRAL position is NOT selected. If the NEUTRAL position is NOT selected, transmission direction control switch (1) must be returned to the NEUTRAL position before a direction can be selected. The power train ECM activates the start relay. Then, the power train ECM allows the engine to start if transmission direction control switch (1) is in the NEUTRAL position. The power train ECM allows the initial selected speed to be changed if transmission direction control switch (1) is in the NEUTRAL position.
Note: Transmission direction control switch (1) must be in the NEUTRAL position when the key start switch is turned to the START position. If switch (1) is not in the NEUTRAL position, the start relay will not be activated when the key start switch is turned.
ReferenceFor more information on the neutral start function, refer to the Service Manual module Systems Operation, "Power Train Electronic Control System" for the machine that is being tested.
ReferenceFor additional information on the transmission direction control switch, the transmission upshift switch, and the transmission downshift switch, refer to the Service Manual module Systems Operation, "Switches" for the machine that is being tested.
ReferenceFor more information on the key start switch, refer to the Service Manual module Systems Operation, "Switches" for the machine that is being tested.
ReferenceFor more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being tested.
ReferenceFor more information on the Integrated Braking System, refer to the Service Manual module Systems Operation, "Integrated Braking System" for the machine that is being tested.