Neutral

pressure and provides oil for charging the torque

(2) Neutral. In neutral, only the front oil

converter (b below).

pump is rotating. Oil is picked up from the sump

through the oil filter element and pumped into

(8) Trimmer valve. At the trimmer valve, main

main pressure circuit. Through various branches of

pressure enters the valve bore at two points. Oil

the main pressure circuit, oil is directed to the

passing into the bore at the lower end of the

trimmer valve flows also through the valve's orifice.

throttle regulator valve, manual selector valve, low-

This pressure is exerted against the bottom of the

intermediate shift valve, lockup valve, flow valve,

main regulator valve, and trimmer valve.

trimmer plug but, due to main pressure plus spring

pressure above the plug, cannot lift it. Oil entering

(3) Throttle regulator valve. At the throttle

regulator valve, main pressure is blocked because

the right side of the trimmer valve bore through an

the valve is downward (when engine throttle is

orifice cannot escape past the extender valve ball

because main pressure plus spring pressure holds

closed, throttle valve is against the stop). Opening

the ball seated. The trimmer is inactive during

the throttle will move the throttle valve upward

neutral operation but is set for operation and will

against a spring. The spring will push the throttle

regulator valve upward and allow oil to flow into

act when any shift (except lockup) manual or

the throttle valve (TV) circuit. Further movement

automatic occurs. Refer to paragraph 2-16i, for

will allow oil to flow into the throttle (T) circuit. T

trimmer operation.

and TV are regulated pressures which increase as

(9) Rear pump check valve. The rear pump

check valve ball is seated during neutral operation

the throttle is opened. Their effects will be ex-

plained in subsequent paragraphs.

(when vehicle is standing) because the rear pump is

not operating. Oil from the main pressure circuit

(4) Manual selector valve. At the manual

passes through an orifice between the front and rear

selector valve, main pressure fills the valve bore at

pump output lines and supplies oil, through a

the valve detent area. In neutral position of the

second orifice, to fill the rear governor pitot ring.

manual selector valve, main pressure flows only to

b. Converter-In Circuit (yellow--fig. 2-3).

the area above the low-intermediate shift plug. This

holds the low-intermediate shift plug downward

(1) The converter-in circuit is supplied from oil

escaping at the main regulator valve. The volume of

and the low-intermediate shift valve and blocker

this oil varies with engine speed (and vehicle speed

plug upward. This action is of no consequence

when vehicle is moving forward). Slight and / or

during neutral operation.

temporary changes in volume will be caused by

(5) Lockup valve. At the lockup valve, main

shifting, action of the throttle valve, lockup valve,

pressure is available for lockup but is blocked

trimmer valve, or inhibitor valves. However, in

because the valve is downward. The valve will

neutral, only the throttle valve can be actuated.

remain downward in neutral because no front

(2) Converter-in oil flows to three points.

governor (G1) pressure is available in neutral or

Trhese are an orifice to the converter-in line, the

reverse (c below).

(6) Flow valve. At the flow valve, main

lockup valve, and the converter-in regulator valve:

pressure enters the valve bore at three points. In

In neutral, or at any other time the lockup valve is

neutral, pressure at these three points is equal.

downward (converter operation), the orifice is

Pressure at the middle point is blocked. The lower

ineffective. It is ineffective because oil can flow

surface area of the valve is slightly greater than the

unrestricted to the converter-in line through the

upper surface area. As a result, the valve is held

lockup valve bore. The branch leading downward

upward against its stop. The action of the flow

to the converter-in regulator valve exhausts ex-

valve is dependent upon a significant flow of oil

cessive oil to the sump when the valve opens.

through the orifice at the left of the valve (para 2-

(3) The converter-in regulator valve opens

16a(1)). A branch of main pressure extends from

when the pressure in the circuit exceeds a

the flow valve bore, when the flow valve is upward,

predetermined value. Input speed (and output

to the area between the extender valve and the

speed) and position of the lockup valve influences

extender valve ball above the trimmer.

its opening and degree of opening. It is shown in the

closed position in neutral because the engine is

(7) Main regulator valve. At the main

regulator valve, pressure acting against the lower

idling, only the front pump is supplying oil, and

surface area of the valve's large land raises the

there is unrestricted flow to the converter.

valve against spring pressure. This produces main

2-9