DAF LF45, LF55 Series. Manual - part 234

©

 200508

1-1

General

PNEUMATIC GEARBOX CONTROL

ΛΦ45/55 series

3

3

1. GENERAL

1.1 LOCATION OF COMPONENTS IN PNEUMATIC SECTION OF GEARBOX 

CONTROL

1

4

3

2

V3 00 360

1.

Filter/governor

2.

Neutral position valve

3.

Electropneumatic downshift protection valve

4.

Range group engaging cylinder

PNEUMATIC GEARBOX CONTROL

1-2

©

 200508

General

3

ΛΦ45/55 series

3

1.2 PNEUMATIC DIAGRAM, GEARBOX CONTROL

N

V

1

1

21

GP

H

L

H

L

4

1

21

22

V3 00 359

4

5

6

2

1

3

+

1.

VIC electronic unit

2.

Electropneumatic downshift protection valve

3.

Range group engaging cylinder

4.

Neutral position valve

5.

Filter/governor

6.

Range group operating switch

L

Position "low"

H

Position "high"

N

Gearbox selector shaft in neutral

V

Gearbox selector shaft engaged

©

 200508

1-3

General

PNEUMATIC GEARBOX CONTROL

ΛΦ45/55 series

3

3

1.3 SYSTEM DESCRIPTION, PNEUMATIC SECTION OF GEARBOX CONTROL

The pressure in the pneumatic section of the 

gearbox control is filtered and reduced in the 

filter/governor (5). From the filter/governor the 

system pressure goes to the neutral position 

valve (4) and the range group operating switch 

(6) located on the ball of the gear lever.

When the range group operating switch is 

activated a pneumatic command will be sent 

to the electropneumatic downshift protection 

valve (2).

N

V

1

1

21

GP

H

L

H

L

4

1

21

22

V3 00 359

4

5

6

2

1

3

+

PNEUMATIC GEARBOX CONTROL

1-4

©

 200508

General

3

ΛΦ45/55 series

3

The electropneumatic downshift protection valve 

can only be activated when the vehicle speed is 

below a certain value. This is so as to prevent 

damage to the drive line. When the vehicle speed 

is low enough, the electropneumatic downshift 

protection valve is activated and the system 

pressure goes from the neutral position valve to 

the range group engaging cylinder.

The neutral position valve is activated when the 

gear lever is moved through the neutral position.