Gradall 534B (9103-1390) Service Manual - Manual (Page 61)

FORWARD/REVERSE LEVER
(Neutral)
When Forward/Reverse Lever is in neutral
position, electrical contacts are not made at the
Fwd/Rev Switches (J) and the oil flow in the circuit
is as follows:
Oil from reservoir (A) is drawn into the main pump
section (B) . It then flows to the priority valve (D)
where a portion is available for the steering circuit.
The oil leaves the priority valve and goes into the
Forward/Reverse Valve
(E) where it is exposed to a
relief valve set at 3000 psi. Since it has not been
activated from the Fwd/Rev Switches
(J) the
Fwd/Rev Pilot Pressure Control Valve (F) keeps it in
neutral and oil passes thru and goes back to the
reservoir.
FORWARD/REVERSE LEVER
(Shifted)
With the Fwd/Rev control lever shifted forward,
1st, 2nd or reverse, electrical contact is made at the
Fwd/Rev Pressure Control Valve (F) and
depending on the position (forward or reverse) pilot
oil is sent to the end caps of the Fwd/Rev Valve (E).
The plunger shifts and oil is routed back to the rear
drive motors (L).
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