Gear selection, function

After the gear control (GS) shift control unit (A15) has been actuated, the signals are read in by the gear control (GS) electronic control unit (A16). This actuates the corresponding solenoid valves of the shift cylinders in order to implement the driver request, taking into account operational safety.

An electromechanical system in the gear control (GS) shift control unit (A15) gives the driver tangible and visual confirmation of the shift operation in a display on the instrument panel. In the event of incorrect operation, an audible warning is given by the warning buzzer.

The gearshift is only performed if the driver has depressed the clutch pedal fully and for a sufficiently long period.

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If the clutch pedal is released prematurely, the transmission automatically shifts into the neutral position. Transmission position "N" is indicated visually by means of a flashing indicator lamp in the display and tangibly by means of a clicking noise at the gearshift lever. At the same time the warning buzzer sounds.

If the clutch is disengaged again within 2 s without the gearshift lever or the half-gear rocker switch being operated, the gear most suited for the particular operating state is automatically engaged.

The gear selection can be performed by the electronics of the gear control (matched to the momentary operating state of the vehicle), or manually by the driver.

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Gear selection by electronics of gear control

The driver determines the shift direction by operating the gearshift lever. The electronics determines the suitable gear for the selected shift direction on the basis of the momentary operating conditions.

Driving on-road:

- Gearshift lever to front = Upshift (min.  gear)

- Gearshift lever to rear = Downshift (min.  gear)

If differential locks engaged (construction site operation):

- Gearshift lever to front = Upshift (max. 1 gear)

- Gearshift lever to rear = Downshift (min. 1 gear)

 The transmission shifts only in the selected shift direction.

Shift facilities:

 Shifting without gear preselection

- Disengaging the clutch

- Move gearshift lever into the desired shift direction until a resistance is felt and hold with a slight pressure. It is only possible to remove the gearshift lever further after the shift has been completed. At the same time the gear stage engaged is shown in the display.

- Engaging the clutch

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 Shifting with gear preselection:

- Move gearshift lever in the shift direction until a resistance is felt and then release

- The gear stage which is preselected in this way remains stored for approx. 10 s (for approx. 30 s in the case of construction site operation) and is indicated by a flashing lamp in the display

During the preselection time

- the preselected gear stage is automatically matched to the altered driving situation

- it is possible to alter the gear stage

- it is possible to cancel the preselection

- Disengaging the clutch

The completed shift is shown in the display.

- Engaging the clutch

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Gear selection by driver

The driver determines the shift direction and the gear stage by operating the gearshift lever and the skip-shift button or the half-gear rocker switch.

Upshift (max. 2 gears):

- By  gear = Pull half-gear rocker switch upwards once.

- By 1 gear = Press and hold function key, then pull gearshift lever forwards or pull half-gear rocker switch up twice (with preselection).

- By 1 gears = Press and hold function key, then pull half-gear rocker switch up and gearshift lever to front or pull half-gear rocker switch up three times (with preselection).

- By 2 gears = Press and hold function key, then pull gearshift lever forwards twice or pull half-gear rocker switch up four times (with preselection).

 If differential locks engaged (construction site operation)

it is possible to shift up by max. 1 gear.

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Downshift:

- By  gear = Push half-gear rocker switch down once.

- By 1 gear = Press and hold function key, then pull gearshift lever to rear or push half-gear rocker switch down (with preselection).

- By 1 gears = Press and hold function key, push half-gear rocker switch downwards and push gearshift lever to rear or push half-gear rocker switch down three times in succession (with preselection).

 It is also possible to shift more than 1 gears.

The warning buzzer sounds if the selected gear stage is too low and the engine would overrev. A downshift is performed into a gear stage which is still permissible.

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Shift facilities:

 Shifting without gear preselection (only  or 1 gear possible)

- Disengaging the clutch

- Move gearshift lever into the desired shift direction until a resistance is felt and hold with a slight pressure. It is only possible to remove the gearshift lever further after the shift has been completed. At the same time the gear stage engaged is indicated by a lamp in the display

- Engaging the clutch

 Shifting with gear preselection

- Move gearshift lever in the shift direction until a resistance is felt and then release

- The gear stage which is preselected in this way remains stored for approx. 10 s (for approx. 30 s in the case of construction site operation) and is indicated by a flashing lamp in the display

- During the preselection time the programmed gear stage may be changed and the preselection deleted

- Disengaging clutch
The completed shift operation is indicated in the display

- Engaging the clutch

 Transmission neutral position "N" and reverse gear cannot be preselected.

Emergency shift:

Actuation of the emergency switch in the gear control (GS) shift control unit (A15) causes the appropriate gear, gate or range solenoid valves to be actuated. This results in air being admitted to the relevant working cylinders thus shifting the gears.

When in emergency shift mode only 2nd gear, 5th gear, neutral and the reverse gear are available. It is possible to shift from 2nd gear into 5th gear when driving. The other gears can only be shifted when the vehicle is stationary and the engine running.