CHANNEL AS 7W1559 - Caterpillar

Second Speed Reverse
Illustration 16 g01093540
(17) Clutch 4 (second speed) (23) Clutch 3 (reverse) (41) Pump oil (42) Torque converter oil (43) Lubricating oil (44) Machine ECM (45) Transmission relief valve (46) Torque converter (48) Torque converter outlet relief valve (49) Oil cooler (50) Modulating valve for clutch 4 (second speed) (53) Modulating valve for clutch 3 (reverse) (55) Torque converter inlet relief valve (56) Sump (57) Pump (58) Filter (59) Return oilThe machine ECM (44) determines the proper clutches that need to be engaged. The proper clutch engagement is based on the inputs to the machine ECM. Some of the inputs that are considered are machine speed, engine speed, and operator inputs.The machine electronic control module (ECM) modulates the electrical current that is sent to the selected clutch solenoids. The clutch solenoids are located on the modulating relief valves. Modulating the current to the clutch solenoid controls the clutch pressure by shifting the spool in the modulating valve.When the transmission direction and speed control lever is moved to the SECOND SPEED REVERSE position, both the solenoid on the modulating valve for clutch 4 (50) (second speed) and the solenoid on the modulating valve for clutch 3 (54) (reverse) are energized. When the solenoid on the modulating valve for clutch 3 (54) is energized, the modulating valve directs pump oil (41) to clutch 3 (23) in order to engage the clutch. When the solenoid on the modulating valve for clutch 4 (50) is energized, the modulating valve directs pump oil (41) to clutch 4 (17) in order to engage the clutch.The oil in the clutches that are not engaged is sent back to sump (56) and the oil becomes return oil (59) .The transmission relief valve (45) controls the pressure of the pump oil (41) that is supplied to the modulating valves. The transmission relief valve (45) directs the unneeded pump oil to the torque converter (46) as torque converter oil (42). Torque converter outlet oil flows through torque converter outlet relief valve (48) to oil cooler (49) as lubrication oil (43). After the oil cools, the oil flows to the transmission for transmission lubrication. After the transmission is lubricated and cooled the oil drains to the sump (56) .Torque converter inlet relief valve (55) limits the torque converter inlet oil pressure in order to protect the torque converter.
Illustration 17 g01093588
(1) Gear (3) Input shaft assembly (12) Gear (13) Hub assembly (16) Gear (17) Clutch 4 (18) Gear (19) Shaft assembly (21) Hub assembly (23) Clutch 3 (24) Gear (27) Shaft assembly (29) Gear (33) Output shaft assemblyWhen the transmission is in SECOND SPEED REVERSE, clutch 3 (23) and clutch 4 (17) are engaged. Torque from the engine is transferred through the torque converter to input shaft assembly (3). Gear (1) is splined to input shaft assembly (3). Input shaft assembly (3) turns gear (16). Gear (16) turns hub assembly (21). Torque is transferred from input shaft assembly (3) through gear (1) and gear (16) to hub