TM-9-2520-254-34 Direct Support for M113 TX100-1 Transmission 2520-00-066-4240 Download
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(1) Figure 2-9 illustrates the hydraulic system in high-range operation even though the manual selector has been moved to a position which does not indicate high-range operation. This condition results when vehicle (transmission output) speed is too great for safe operation in intermediate-range at the time a manual downshift is made. (2) When the manual downshift is made, rear governor (G2) pressure is sufficient to continue holding the intermediate-high shift plug, shift valve, and blocker plug upward against spring force and inhibitor pressure. This extends high-range operation of the transmission during the period the vehicle is moving at excessive speed. (3) When vehicle speed decreases, G2 pressure also decreases. When G2 pressure falls to a value which will no longer hold the intermediate-high shift plug and valve upward against spring force and inhibitor pressure, the downshift to in- termediate range will occur. This is an automatic shift, which lags behind the manual shift. b. Other Functions Same as 1-2-3 Operation (fig. 2-9). In high-range operation (selector at 1-2 position), the circuits not involved in action of the high-intermediate inhibitor operate as described in paragraph 2-17 for high-range (1-2-3) operation. 2-21. Hydraulic System—Intermediate-Range Operation (Manual Selector at 1—Inter- mediate-Low Inhibitor Acting) NOTE Inhibitors are safety devices which provide some measure of protection against engine overspeed if the operator inadvertently downshifts above prescribed speed. 2-23