Citytrac 4200
Citymaster 1200
Citycleaner
Service Documents
For internal use only
Status
March 2009
Page
46 of 108
5.3.3 Switching valve, work/transport mode
As it progresses, the volume flow from the shut-off unit (output A) to the rear wheel motors is applied to the switching valve (input A).
When in an inactive state (Y13), the volume flow is fed to the rear wheel motors (all-wheel drive).
The two rear motors are connected in series so that the volume flow can be divided as required.
The slower work mode results from distribution of the feed quantity to 4 wheel motors.
When activated (Y13 energised), the solenoid valve switches the feed pressure to the distributing valve and activates it hydraulically.
When at this switch setting (drive on roads), the distributing valve connects the feed side with the outflow side and the feed pressure.
At the same time, a connection from the outflow side of the motors (C), used to exchange the warmed oil, is established to the tank via
an aperture.
The feed (A) to the switching terminal is blocked so that the oil quantity supplied by the pump only needs to be distributed
to the two
front motors
.
This results in the faster transport mode.
