DAF LF45, LF55 Series. Manual - part 235

©

 200508

2-1

Description of components

PNEUMATIC GEARBOX CONTROL

ΛΦ45/55 series

3

3

2. DESCRIPTION OF COMPONENTS

2.1 FILTER/GOVERNOR

Overview drawing, filter/governor

Filter/governor (1) on gearbox

2

3

4

1

5

V300558-2

6
5
4

3

2

1

10

9

8

V300430

7

1.

Filter/governor

2.

Filter element

3.

Seal

4.

O-ring

5.

Cover

6.

Plug

7.

Output

8.

Selector valve output plug

9.

Attachment bolt

10.

Supply pressure input

PNEUMATIC GEARBOX CONTROL

2-2

©

 200508

Description of components

3

ΛΦ45/55 series

3

The full vehicle supply pressure from circuit four 

of the brake system must pass through the air 

filter.

The supply pressure goes through the bore (1) in 

the valve and will force the piston down against 

the spring pressure.

The spring cannot be adjusted.

The system pressure (see "Technical data") goes 

via connection point (2) to the range group 

operating switch and the neutral position valve.

2

1

V302003

©

 200508

2-3

Description of components

PNEUMATIC GEARBOX CONTROL

ΛΦ45/55 series

3

3

2.2 GEAR LEVER SELECTOR VALVE

Changing to the low or high speed range is done 

with switch (A) on the ball of the gear lever.

When the switch is facing down it means that the 

low speed range has been or is being engaged. 

When the switch is facing up the high speed 

range has been or is being engaged.

Pre-selection is possible. A particular range is 

switched only when the gear lever is moved 

through the neutral position.

The pressure on connection 1 is the system 

pressure. When the switch is operated a 

pneumatic command will be sent from connection 

21 to the electropneumatic downshift protection 

valve.

A

V3 00 562

1

21

V3 00 477

PNEUMATIC GEARBOX CONTROL

2-4

©

 200508

Description of components

3

ΛΦ45/55 series

3

2.3 ELECTROPNEUMATIC DOWNSHIFT PROTECTION VALVE

The electropneumatic downshift protection valve 

receives a certain frequency value relating to the 

vehicle speed from the VIC.

If this value is too high, the connection between 

the electropneumatic downshift protection valve 

and earth will be broken. Despite the pneumatic 

command from the range group operating switch 

to connection point (4) on the electropneumatic 

downshift valve, it is not now possible to switch to 

the low range.

The system pressure to connection point (1) on 

the electropneumatic downshift protection valve 

is only available when the gear lever, and hence 

also the neutral position valve, is in the neutral 

position.

1

4

L

H

21

22

V3 00 478