CT660 CX31 and CX31 HT On Highway Truck Power Train Electronic Control System Caterpillar

• UP

• DOWN

• FORWARD

• NEUTRAL

• REVERSE

• MODE

There is an optional lever shift selector. This lever shift selector has identical wiring, similar display, and function.

Note: If you are experiencing trouble with the shifter, refer to Troubleshooting, KENR5099, "Transmission Does Not Respond to Shift Selector".

The CX31 has six forward gears, neutral, and one reverse gear.

Illustration 1	g03872741

The transmission control has six buttons.

(1) Mode

(2) Upshift Arrow

(3) Downshift Arrow

(4) "D" button

(5) "N" button

(6) "R" button

Refer to Operation and Maintenance Manual, "Transmission Control".

When the transmission control is in the NEUTRAL position (5) , the neutral lock prevents the transmission control from being accidentally moved into a gear position.

Press the neutral lock switch, and move the transmission control forward or backward in order to select the following gears.

"R" - The "R" indicates the reverse gear. Pressing this button causes the transmission to shift into the reverse gear.

"N" - The "N" indicates the transmission neutral position. Pressing this button causes the transmission to shift to neutral.

"D" - The "D" button indicates the forward gears. Pressing this button will cause the transmission to shift into the first gear in the forward direction.

"Mode" - Mode Selector

"Arrow" - Upshift

"Arrow" - Downshift

Stop the vehicle and ensure that the engine is at low idle. When you move the transmission control from the NEUTRAL position to the FORWARD position, the first gear and the torque converter drive will be engaged.

As you increase engine speed and the ground speed increases, the transmission will upshift. As the ground speed continues to increase, the transmission will upshift automatically until the selected gear is reached.

If the ground speed is reduced or the engine speed is reduced by an increased load, the transmission will automatically downshift in order to select the correct gear. The transmission downshifts one gear at a time in order to select the correct gear.

A downshift inhibitor prevents the operator from forcing a downshift. When the vehicle is in motion and the gearshift selector is moved to a lower gear, the transmission will not force a sudden downshift. The transmission will not downshift until the proper ground speed is achieved.

Checking the Oil Level The gearshift selector can be used in order to initiate the oil level check. The check is initiated by pressing the up arrow and the down arrow on the keypad simultaneously. The status of the oil level is displayed on the digital display.

Basic Operation

Illustration 2	g01343907
Display showing the NEUTRAL position.

The display on the gearshift selector will display a pair of "Ns" when the key start switch is in the ON position. The display indicates that the transmission is in Neutral.

Range Selection

Push the "D" in order to shift to a forward gear or the "R" in order to shift to a reverse gear.

Note: The transmission will not shift into a gear from Neutral or between a forward "D" and reverse "R" gear when the engine RPM is over 1000 RPM.

Forward Range

Illustration 3	g01343917
Display showing the first gear forward.

Note: 3 shows that the transmission is in first gear and that a total of six gears is available.

The gearshift selector will display the maximum gear that is available on the transmission on the left side of the display and the actual gear on the right side of the display when "D" is selected. The transmission continues to shift the actual gear when it's displayed on the right side of the display. An upshift or a downshift may be forced by pressing one of the arrows on the right side of the gearshift selector when the transmission is in a forward range.

Manual Selection of the Highest Desired Forward Gear

The maximum desired gear of the transmission is limited for certain operations of the vehicle. When D is selected, the maximum desired gear is displayed. By using the up arrows and the down arrows on the shift pad, the maximum desired gear can be selected. Pressing the up arrow will raise the maximum desired gear by one gear to the maximum gear that is available. Pressing the down arrow will lower the maximum desired gear by one gear to the minimum gear that is available.

Once the desired gear is selected, the transmission will maintain the gear. The transmission will not shift to a higher gear unless the speed of the vehicle requires a shift. The transmission will shift in order to protect the engine from an overspeed event. The up arrow may be used in order to select the maximum gear when the conditions of operation of the vehicle no longer require the lower maximum gear.

Reverse Range

Illustration 4	g01343923
Display showing the Reverse gear is selected but the transmissions not shifted from Neutral.

Push the "R" button in order to select the reverse range. The display on the gearshift selector displays an "R" on the left side and an "N" on the right side.

Illustration 5	g01343924
Display showing the transmission inReversegear.

When the transmission shifts into a reverse range, the display will have an "R" in both locations. There is only one gear in the reverse range.

Flashing Desired Gear

Several circumstances may prevent the transmission from shifting into a desired range.

Illustration 6	g01343927
The display is showing the desired gear. The transmission is held in the Neutral position.

Circumstances that prevent shifting into the desired gear include the following:

• The engine speed is too high.

• Vehicle speed is too high.

• Programmable parameters

• Auto Neutral

• PTO

• Driveline PTO

• Neutral to Gear Inhibit

• Direction Inhibit

Once the switch and the speed requirements have been met, the transmission may shift normally. Some circumstances may require the operator to select Neutral and then to select the desired range in order for the transmission to shift into the range.

Mode Button

Illustration 7	g01319024

The "MODE" button is available to control various functions. The primary purpose of the button is to select a different shift schedule. The different shift schedules change the fuel economy. Other modes may be selected through the programming of the transmission parameter. When the "MODE" button is pushed, the LED in the upper right corner turns ON and informs the operator that the selected feature is active. Pressing the "MODE" button a second time disables the feature and the LED turns OFF.

Oil Level Check

The shift selector pad allows the operator to check the oil level of the transmission for the operator's station. The following conditions are required for initiating the oil level check:

• Engine at idle

• The vehicle is stationary.

• Transmission oil temperature is more than 80 °C (176 °F).

Simultaneously press the up arrow and the down arrow in order to initiate the transmission oil level check. This action starts a 2 minute timer. If the conditions are not correct for the oil level check to take place, the shift selector pad will display one of the following display codes in Table 1.

Once the conditions have been met, the range display will show "24" and count down to "0" during the 2 minute counter period. At the end of the 2 minute countdown, one of the following display codes in Table 2 will be displayed. The display only shows two characters at a time.

The message for the oil level will continue to display until the operator exits the mode. The mode may be exited by pressing one of the range buttons or by simultaneously pressing the up arrow and the down arrow.