
280 LIGHT AND HEAVY VEHICLE TECHNOLOGY
bands of the governor plug, where it reacts against the
larger band to overcome the effect of governor pressure
on the other side of the plug. By holding the plug in its
bottomed position the fluid at line pressure can then be
transferred to the appropriate friction brake element of
the gearset (Figure 17.10c). Since line pressure is also
directed at both ends of the shift valve, the net effect is
that the valve is positioned by spring load such that
throttle pressure is prevented from acting on it.
As might be expected, the 2-3 shift valve operates in
the same manner as the 1—2 shift valve. However, th ...