AIR SYSTEM (CONT)
Functional Description Auxiliary Loads N
This takes place by means of the pressure relief
valve (29.1). The pressure is approx. 5 PSI/0.35
The auxiliary loads include:
Four-wheel drive and differential locks (G)
Intermediate Speed Shift
Axle vent (H)
The intermediate speeds are pneumatically shifted
with the aid of the shift lever valve (45.4).
Intermediate speed shift (J)
The compressed air supply of the brake system
corresponding control pulses for air entry and
has priority, i.e., a minimum pressure of approx.
escape in the shift cylinder (20.8) in the cascade
80 PSI/5.5 bar is first made available to the brake
The solenoid valve (33.1a) releases the supply air
From a pressure of 80 PSI/5.5 bar, the auxiliary
to the control valve (45.5) only when the clutch is
loads receive their supply via the overflow valve
operated in order to shift speeds.
(7.3) up to an operating pressure of 107 PSI/7.35
The valve (33.1a) is electronically actuated after
the clutch pedal has been fully depressed down to
the contact switch.
Four-Wheel Drive Differential Locks
The four-wheel drive is engaged in the
transmission in position (1) of the changeover
valve (32.1). In position (2) the differential locks of
the axles are additionally activated.
In both positions (1 and 2), the axles receive a
compressed air supply at slight pressure for