and causes engagement of the forward sprag unit.
Likewise, if the reverse sprag unit is engaged, the front
When the transmission is shifted into reverse, the air
wheels cannot be turned in a forward direction. Also, if a
cylinder control valve admits air to the opposite side of
vehicle with air pressure in the system is parked with the
the piston, causing engagement of the reverse sprag
transmission shift lever in neutral position, it cannot be
unit. When the forward sprag unit is engaged, the front
pushed backward until the transmission shift lever is
wheels will freewheel or turn only in a forward direction.
shifted to reverse.