TM-9-2520-254-34 Direct Support for M113 TX100-1 Transmission 2520-00-066-4240 Download

(2) Neutral. In neutral, only the front oil pump is rotating. Oil is picked up from the sump through the oil filter element and pumped into main pressure circuit. Through various branches of the main pressure circuit, oil is directed to the throttle regulator valve, manual selector valve, low- intermediate shift valve, lockup valve, flow valve, main regulator valve, and trimmer valve. (3) Throttle regulator valve. At the throttle regulator valve, main pressure is blocked because the valve is downward (when engine throttle is closed, throttle valve is against the stop). Opening the throttle will move the throttle valve upward against a spring. The spring will push the throttle regulator valve upward and allow oil to flow into the throttle valve (TV) circuit. Further movement will allow oil to flow into the throttle (T) circuit. T and TV are regulated pressures which increase as the throttle is opened. Their effects will be ex- plained in subsequent paragraphs. (4) Manual selector valve. At the manual selector valve, main pressure fills the valve bore at the valve detent area. In neutral position of the manual selector valve, main pressure flows only to the area above the low-intermediate shift plug. This holds the low-intermediate shift plug downward and the low-intermediate shift valve and blocker plug upward. This action is of no consequence during neutral operation. (5) Lockup valve. At the lockup valve, main pressure is available for lockup but is blocked because the valve is downward. The valve will remain downward in neutral because no front governor (G1) pressure is available in neutral or reverse (c below). (6) Flow valve. At the flow valve, main pressure enters the valve bore at three points. In neutral, pressure at these three points is equal. Pressure at the middle point is blocked. The lower surface area of the valve is slightly greater than the upper surface area. As a result, the valve is held upward against its stop. The action of the flow valve is dependent upon a significant flow of oil through the orifice at the left of the valve (para 2- 16a(1)). A branch of main pressure extends from the flow valve bore, when the flow valve is upward, to the area between the extender valve and the extender valve ball above the trimmer. (7) Main regulator valve. At the main regulator valve, pressure acting against the lower surface area of the valve’s large land raises the valve against spring pressure. This produces main pressure and provides oil for charging the torque converter (b below). (8) Trimmer valve. At the trimmer valve, main pressure enters the valve bore at two points. Oil passing into the bore at the lower end of the trimmer valve flows also through the valve’s orifice. This pressure is exerted against the bottom of the trimmer plug but, due to main pressure plus spring pressure above the plug, cannot lift it. Oil entering the right side of the trimmer valve bore through an orifice cannot escape past the extender valve ball because main pressure plus spring pressure holds the ball seated. The trimmer is inactive during neutral operation but is set for operation and will act when any shift (except lockup) manual or automatic occurs. Refer to paragraph 2-16i, for trimmer operation. (9) Rear pump check valve. The rear pump check valve ball is seated during neutral operation (when vehicle is standing) because the rear pump is not operating. Oil from the main pressure circuit passes through an orifice between the front and rear pump output lines and supplies oil, through a second orifice, to fill the rear governor pitot ring. b. Converter-In Circuit (yellow—fig. 2-3). (1) The converter-in circuit is supplied from oil escaping at the main regulator valve. The volume of this oil varies with engine speed (and vehicle speed when vehicle is moving forward). Slight and / or temporary changes in volume will be caused by shifting, action of the throttle valve, lockup valve, trimmer valve, or inhibitor valves. However, in neutral, only the throttle valve can be actuated. (2) Converter-in oil flows to three points. Trhese are an orifice to the converter-in line, the lockup valve, and the converter-in regulator valve: In neutral, or at any other time the lockup valve is downward (converter operation), the orifice is ineffective. It is ineffective because oil can flow unrestricted to the converter-in line through the lockup valve bore. The branch leading downward to the converter-in regulator valve exhausts ex- cessive oil to the sump when the valve opens. (3) The converter-in regulator valve opens when the pressure in the circuit exceeds a predetermined value. Input speed (and output speed) and position of the lockup valve influences its opening and degree of opening. It is shown in the closed position in neutral because the engine is idling, only the front pump is supplying oil, and there is unrestricted flow to the converter. 2-9