Normal Operation
The Machine ECM receives the operator's requested speed for and direction from the FNR Shift Handle - Autoshift over the Cat Data Link.
The control module will direct the operation of the transmission's solenoids when the following prerequisites are established. The shift lever is communicating to the control module and the control module has received the gear information.
The actions of the Machine ECM are based on the status of the following components:
- Auto/Manual Switch
- Neutral Lock Switch
- Shift lever control module - FNR Autoshift
- Neutralizer/Downshift Switch
- Parking Brake Switch
- Ride Control Switch
The Autoshift transmission is controlled by a twist handle. The handle is located on the shift lever control module. The Autoshift twist handle has four positions.
High Speed Directional Shift
No precaution is taken when the machine's direction is shifted by the Autoshift transmission control. If you shift from the fifth gear forward to the third gear reverse, the transmission will shift to third gear reverse.
Power Up
When the Machine ECM is energized, the transmission is placed in neutral. This is done regardless of the shift lever's position. Prior to travel, the shift lever must pass through the NEUTRAL position. The transmission will remain in neutral until this has been accomplished.
Neutral Start
The signal for the start relay goes through the shift lever. The shift lever must be in the NEUTRAL position in order to allow cranking of the engine. The lever must pass through the NEUTRAL position before a direction can be selected.
Modes of Operation
The FNR Shift Handle - Autoshift has an automatic shift function and a manual shift function.
Ride Control
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| Illustration 1 | g01443531 |
Ride control circuit | |
Ride Control Switch: This switch provides two inputs to the Machine ECM.
- "Ride control automatic operation"
- "Ride control ON"
- "Ride control OFF"
A three-position switch controls the ride control function. In the held middle OFF position, the ride control function is disabled. In the ON position, the ride control solenoid is always enabled. In the held AUTO position, the ride control function activates the ride control solenoid valve when the ground speed is greater than a set limit. The ride control solenoid valve is deactivated when the machine ground speed is at least 1 km/h less than the set speed limit. The default set limit for the AUTO position is 9 km/h. Caterpillar Electronic Technician (ET) will be used to change the set limit. For the purpose of calculating ground speed, a nominal tire radius of 635 mm (25 inch) shall be used. A pressure switch is placed in series with the ride control relay that controls the solenoid. When there is pressure on the rod end of the lift cylinder, the circuit of the solenoid driver is open. The ride control function will be prevented from being engaged when there is a load on the rod end, such as when the loader is being used as a stabilizer. Use of a relay driver also prevents diagnostics from being performed on the ride control solenoid circuit.
Ride Control Disable: A pressure switch within the rod end of the lift cylinder is used in order to sense when the loader is applying a downward force. The switch deactivates at 3137 ± 175 kPa (455 ± 25.4 psi). The control module will disable the ride control function by de-energizing the ride control relay.
Ride Control Enable: A pressure switch within the rod end of the lift cylinder is used to sense when the loader is administering a downward force. The switch is activated at a maximum pressure of 3500 kPa (508 psi). The control module will enable the ride control function by energizing the ride control relay. The ride control enable input is activated by the operator and sent to the Machine ECM. The ride control will be enabled when this input has +battery voltage.
Parking Brake
The parking brake uses the following components:
- Machine Electronic Control Module
- Parking Brake Switch
- Parking Brake Indicator
The parking brake switch alerts the Machine ECM of the status of the parking brake. The brake can be applied or the brake can be released.
The machine will remain in neutral under the following conditions:
- The parking brake is applied and the machine is placed in gear.
- The machine is in gear and the parking brake is applied.
The shift lever must be shifted back to the NEUTRAL position and the parking brake released in order to resume normal operation.
The Drive Through Operation of the Parking Brake:
1 - The parking brake is applied and the shift lever is in the NEUTRAL position.
2 - Shift the machine into gear.
3 - shift the machine back into the NEUTRAL position.
4 - Within 3 seconds, shift the machine back into gear.
The in−gear relay will energize. A parking brake abuse event will be logged in the control module. Releasing the parking brake will silence the alarm. This leaves the machine in normal operation. The alarm is also silenced when the machine is in neutral.
Transmission Auto/Manual Switch
The Transmission auto/manual switch supplies 2 switch to ground inputs. The inputs are used in order to select the automatic shift function or the manual shift function of the FNR Shift Handle - Autoshift. The switch has diagnostic capabilities.
When auto/manual input "auto" is to ground and auto/manual input "man" is open, the automatic mode is selected. When auto/manual input "auto" is open and auto/manual input "man" is to ground, the manual mode is selected.
If the inputs are identical (both open or both ground) for a minimum of five seconds, a diagnostic fault is logged. The machine will default to the manual shift function. When the Auto/Manual switch is used, the shift lever does not need to first pass through the NEUTRAL position to make the switch from AUTO to MANUAL or from MANUAL to AUTO.
Neutral Lock
When the neutral lock switch is depressed, the feature holds the machine in neutral. The switch signals the transmission control to ignore shift lever's position. Depressing the switch signals the control module to ignore the shift lever. All of the transmission solenoids remain inactive. This holds the machine in neutral.
The machine's neutral lock uses the following components:
- Machine Electronic Control Module
- Neutral Lock Switch
If the neutral lock switch is depressed and the machine is in gear, the control module will immediately shift the machine into neutral. The transmission will remain in neutral until the shift lever is returned to the NEUTRAL position and the neutral lock is turned off.
When the neutral lock switch is closed to ground the transmission is placed in neutral regardless of the state of the shift lever. The transmission remains in neutral until the neutral lock switch is opened and the shift lever is placed in neutral. This must happen before the machine is placed in gear.