TM-9-2520-234-35 Technical Manual for M109 Transmission XTG-411-2A Download

CHAP 2, SEC II DESCRIPTION AND OPERATION OF PAR 22-23 MAIN TRANSMISSION ASSEMBLY 22. MAIN-PRESSURE REGULATOR AND LOCKUP SHIFT VALVE BODY ASSEMBLY a. Components (fig. 383, fold-out 12) (1) This valve body assembly in- cludes the main-pressure regulator valve group, lubrication pressure regulator valve group and the lockup shift valve group. The main-pressure regulator group in- cludes valve assembly 14, plug 13, springs 20 and 21 and plug 19. The lubrication pressure regulator valve group includes valve 9, spring 10 and plug 7. The lockup shift valve group includes valve 26 and spring 27. The lockup shift valve and main-pressure regulator valve groups are retained in the valve body 12 by cover assembly 23. (2) Valve assembly 14 and valves 9 and 26 are spool-type valves which move lengthwise in their bores. All movement is automatic and influenced by spring pres- sures and hydraulic pressures. Passages in valve body 12 receive oil from or direct oil to passages in oil transfer plate 3. The oil transfer plate, in turn, connects these passages with passages in converter hous- ing 31 (fig. 374, fold-out 3). b. Operation (fig. 372 fold-out 1 and fig.383, fold-out 12) (1) Main pressure supplied by the input and output driven pressure pumps is directed into a cavity between two lands of different diameter. Pressure in this area moves valve assembly 14 toward springs 20 and 21. In its movement, the valve uncovers a port which directs oil to the input side of the torque converter. In the absence of any modulating pressures (lockup, high-range or reverse) the valve assumes a position wherein main pressure balances the compression of springs 20 and 21. (2) When the reverse-range clutch is applied, reverse-range clutch pressure acts against plug 19. This action assists the springs 20 and 21 and raises main pressure. When the high-range clutch is applied, high-range clutch pressure acts against plug 13. This action pushes the valve against springs 20 and 21, lowering main pressure. When the lockup clutch is applied, lockup clutch pressure acts against the smaller end of valve assembly 14. This action pushes the valve toward springs 20 and 21, lowering main pressure. (3) Oil returning from the oil cooler acts against the stem end end of lubrication regulator valve 9, pushing it against spring 10. The valve moves toward the spring and uncovers a port which di- rects oil to transmission sump. The result- ing pressure at the stemmed end of the valve supplies the lubrication system while the bulk of the oil returning from the cooler flows to the sump. (4) The lockup shift valve 26 has two functions. It controls the application and release of the lockup clutch and it regulates the volume of oil flowing to the torque converter. Three hydraulic pres- sures and spring 27 control the movement of the valve. When only spring pressure is acting, the valve directs a large volume of oil to the torque converter and allows the lockup clutch to release by exhausting its apply line. (5) Governor pressure acts against one end of the lockup shift valve and pushes the valve against spring 27. When turbine speed is sufficient, governor pressure moves the valve against the spring. When this occurs, oil is directed to the lockup clutch, applying it. Simultane- ously, the passage of oil to the torque con- verter is reduced. T and TV pressures act against the spring-loaded end of the lockup shift valve. These pressures, when present, modulate the effect of governor pressure at the opposite end of the valve. At closed throttle, T and TV are absent. At light throttle, TV is present. At full throttle, both are present. Thus, the governor pres- sure (and turbine shaft speed) required to cause lockup will vary with the degree of throttle opening. 23. OUTPUT PRESSURE OIL PUMP ASSEMBLY a. Components (fig. 384, fold-out 13) (1) The pump assembly includes gear 11, gear 14, needle bearings 7, 13 and 17, shaft 10, body 8 and cover 19. Gear 11 22 Change 2