Hydraulic 2/4 Wheel Drive Unit - Pressure On/Spring Off - Manitowoc Grove 5540F Service Manual

TRANSMISSION AND TORQUE CONVERTER
Hydraulic 2/4-Wheel Drive Unit
- Pressure ON/Spring OFF
4-Wheel Drive Operation (See Figure 7-12)
This clutch is of the 'Pressure-ON (4WD)/Spring-OFF (2WD)'
type. The clutch is engaged and disengaged by introducing
or dumping pressurised oil behind piston C via a solenoid
valve A. The solenoid valve is operated by a switch in the
cab.
When the switch is in the 4-wheel drive position, solenoid
valve A is energized. The energized solenoid A1 causes the
valve spool to move and form a connection between ports 3
and 2.
Pressurised oil is directed to piston C via ports 3 and 2. The
piston moves, against spring D, to press the friction/counter
plates of clutch pack B together, thus driving the output yoke
E.
A406200
7-12
Published 10-21-2010, Control# 198-04
5540F/YB5515 SERVICE MANUAL
FIGURE 7-12