b. Forward-Reverse Inhibitor Hydraulic Circuit (fig. 1-49). The
forward and reverse valves determine the direction of transmission
operation.
A solenoid controls each of the spring loaded valves,
ensuring hydraulic pressure to the proper clutch at the correct time.
The forward-reverse inhibitor prevents the transmission from making
forced directional changes at excessive speed. Output speed governor
(G2) pressure opposes the spring pressure to prevent movement of the
forward shift valve flow and flow of the hydraulic fluid within the
transmission.
Figure 1-49.
Forward, Reverse, and Inhibitor Valve Circuit.
c. Priority Valve Circuit (1-50).
The priority valve receives
oil from the neutral shift valve and directs it to the shift valves.
The priority valve prevents sudden loss of main pressure ahead of the
range control due to the high flow demand when applying a range
clutch. During braking operations, brake apply pressure assists the
spring end of this valve to maintain the same amount of pressure
passing through the valve.
49
OD1710
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