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

PAR 9-11 DESCRIPTION AND OPERATION OF CHAP 2, SEC II MAIN TRANSMISSION ASSEMBLY is inherent with fluid drives and torque converters without lockup. 10. INPUT PRESSURE AND SCAVENGE OIL PUMP ASSEMBLY a. Components (fig. 373, fold-out 2) (1) A 2-section, gear-type pres- sure and scavenge oil pump 45 is located on the input transfer housing. It is driven by the input transfer gears and rotates at any time the vehicle engine rotates. One section is the input pressure pump. The other (smaller) section is the scavenge pump. The assembly includes a pump drive gear 57, pump idler gear 58, two scavenge pump gears 55 and 56, pressure pump body 61, scavenge pump body 47, four needle bearings 53, 54, 59 and 60, and separator plate 50. (2) Pump drive gear 57 and idler gear 58 are the input pressure pump ele- ments. Scavenge pump gear 56 is keyed to the shaft of the drive gear 57 by key 51. Gear 55 is mounted on shaft of gear 58. The drive and driven gears are supported in the pump bodies 47 and 61. Separator plate 50 divides the pump sections. b. Operation (1) The input pressure section of the pump supplies oil under pressure to the power train for control, lubrication and converter charging. This oil is picked up from the sump of the main transmission section and pumped into the hydraulic system, passing first through the main oil screen assembly. (2) The scavenge section of the pump picks up oil which collects in the input transfer gear housing and converter housing, and returns it to the sump of the main transmission section. The source of this oil is lubrication of the input transfer gears and bearings. (3) The pump assembly rotates at approximately 1.62 times engine speed and in the same direction as the engine. Section II. DESCRIPTION AND OPERATION OF MAIN TRANSMISSION ASSEMBLY 11. HIGH-RANGE CLUTCH AND GOVERNOR a. High-range Clutch and Governor Components (fig. 375, fold-out 4) (1) The high-range clutch in- cludes a housing assembly 73, a piston as- sembly 67, four (XTG 411-2A) or five (XTG 411-4) plates 57, five plates 56, re- action plate 59, return springs 66 and re- tainer 65. The high-range clutch hub is integral with the intermediate-range car- rier assembly 16 (fig. 376, fold-out 5). A governor ring is riveted or welded to the clutch housing assembly 73 (fig. 375, fold- out 4). (2) Pitot tube 76 is a governor component. It is mounted by two bolts 14 to transmission housing 17. The high-range clutch and governor ring rotate. b. Operation of High-range Clutch and Governor (fig. 375, fold-out 4) (1) The high-range clutch trans- mits torque at 1:1 ratio from the conver- ter turbine shaft to the high-range clutch hub and, in turn, through the low- and intermediate-range planetaries, which are locked together, to the transmission out- put shaft. When hydraulic pressure is di- rected to the cavity between piston as- sembly 67 and housing assembly 73, the piston compresses internal-splined 56 and external-splined 57 plates against reaction plate 59. This locks the high-range clutch hub (located on the intermediate-range planetary carrier) to the clutch housing, and transmits converter output torque directly to the transmission range output shaft. (2) When hydraulic pressure is exhausted from the clutch cavity, springs Change 2 13