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

throttle valve (TV) pressure is connected to the throttle (T) pressure circuit. From this point, and throughout the remaining throttle opening movement, TV and T pressures are equal. Both increase as the throttle is opened. Throttle (T) pressure is directed to the upper surface areas of the low-intermediate shift valve, intermediate-high shift valve, and the lockup valve. (2) At the low-intermediate shift valve, T pressure is exerted downward on the shift valve and upward on the blocker plug. This pressure tends to hold the shift valve downward against the low- intermediate shift plug which is being pushed upward by G2 pressure. Thus, throttle opening delays upshifting. The greater throttle opening is, the greater is upshift delay. (3) At the intermediate-high shift valve, the effect of T pressure is identical to that described in (2) above. However, the transmission speed range (and G2 pressure range) within which the movement of each of the shift values occurs is different. This difference is caused by the difference in spring loads and plug areas against which G2 pressure works. Thus, the low-intermediate shift valve, working with the lighter spring and greater plug area, will upshift at a lower vehicle speed (and G2 pressure) than will the intermediate-high shift valve. (4) At the lockup valve, T pressure delays the upward movement of the lockup valve and thus delays lockup. The delay varies with throttle opening. Should the throttle be closed completely while the transmission is in low range, there would be no T pressure or TV pressure to inhibit the upward movement of the lockup valve. (5) Throttle (TP) pressure can cause a downshift at full throttle under certain conditions as well as preventing an upshift under some con- ditions. T pressure can also cause a change from lockup operation to converter operation by moving the lockup valve downward. Input and output speed and governor (G1 and G2) pressures in- fluence the point at which upshifts, downshifts, or lockup occur when the throttle is manipulated. h. Inhibitor Pressure Circuit (dotted red—fig. 2- 4). (1) In low-range operation, the intermediate- low and high-intermediate inhibitor circuits are charged. The only function of these pressures in low-range operation is to prevent the upshifting of either shift valve. (2) In the intermediate-low inhibitor circuit, oil enters (from main) through an orifice and exerts pressure against the upper surface areas of the inhibitor valve and the blocker plug. The inhibitor valve moves downward against its spring and allows oil to escape from the exhaust port at the left side of the valve bore. The escape of oil at the exhaust port, coupled with the limited flow caused by the restriction in the feed line, causes a reduced pressure in the inhibitor circuit. This reduced pressure is calibrated against the downward force required to downshift the low-intermediate shift valve at a specific vehicle speed (and specific G2 pressure). (3) In the high-intermediate inhibitor circuit, hydraulic action is identical to that described in (2) above, except that calibration of the pressure is to that required to downshift the intermediate-high shift valve. (4) In low range, oil escapes continuously at the exhaust ports in the inhibitor bores. i. Lockup Clutch Circuit (blue, white—fig. 2-4). When the lockup valve is upward, main pressure supplies the lockup feed line. When the flow valve is upward, pressure in the lockup feed line supplies oil to the lockup clutch circuit. Lockup pressure applies the lockup clutch. 2-16. Hydraulic System—Intermediate-Range Operation a. Main Pressure Circuit (red—fig. 2-5). (1) The main pressure circuit in intermediate range functions as described in paragraph 2-15a for low-range operation except for the differences outlined in (a) through (e) below. (a) Main pressure is cut off from the passage (line 2) leading to the intermediate-low inhibitor circuit. (b) Main pressure is extended from the low- intermediate shift valve bore to the intermediate- high shift valve bore. (c) Because a clutch (intermediate range) is in the initial stage of being charged, there is a rapid flow of oil through the orifice at the left side of the flow valve. This reduces the pressure downstream of the orifice and causes the flow valve to move downward. (d) The downward position of the flow valve temporarily releases lockup clutch pressure. In addition, main pressure is cut off from the line leading to the area above the extender valve ball. This permits pressure above the trimmer plug to escape past the extender valve ball and to exhaust finally through the same port at the right of the flow valve bore through which lockup pressure exhausts. (e) Release of pressure above the trimmer plug permits the trimmer plug to move upward. This, in turn, permits the trimmer valve to move upward until main pressure escapes at the exhaust port at the left of the trimmer valve bore. (2) The results of the differences in the main pressure circuit are explained in the various circuit explanations which follow. b. Converter-In Circuit (yellow—fig. 2-5). The converter-in circuit functions as described in paragraph 2-15b. 2-14