HYDRAULIC SYSTEM – Continued

TM 9--2520--215--34 0005 00--7 THEORY OF OPERATION -- CONTINUED 0005 00 HYDRAULIC SYSTEM – Continued Action Of Hydraulic System In Intermediate Range, Lockup Drive, No Steer NOTE Refer to Torque path in Intermediate Range, Lockup drive, no steer schematic view for the torque path through the transmission. When in high range, lockup drive, left steer, the system functions as described in this work package except that the following additional circuits are opened (or closed) to the action of oil flow and pressure: The range--selector valve directs pressure to the intermediate--range clutch, through the converter lockup tim- er and relay valves, and into the lockup clutch. When the vehicle is moving forward the output--driven brake coolant and pressure pump operates. Oil pressure from the range selector valve applies the intermediate--range clutch. The output--driven brake coolant pump draws air when brakes are released. The air pumped through the output reduction gear assemblies into the transmission gear compartment. The output--driven pressure pump assists the input--driven pump in supplying oil to the system. A throttle--controlled lever pivots on a lug at the top of the relay valve cover. When the engine throttle opens, the plunger compresses a spring against a relay valve. When the vehicle operating in intermediate or high range, the relay valve controls the engagement and release of the lockup clutch. Governor pressure is exerted against the end of the valve. When governor pressure is great enough to overcome the force of the spring, the lockup clutch en- gages. The position of the throttle will determine the vehicle speed at which lockup occurs. At closed throttle, lockup will occur at a lower speed; at open throttle, lockup will occur at a higher speed. In intermediate range, the shift inhibitor will prevent a downshift to low range (or reverse range) until vehicle speed is reduced to a safe level. Torque Path in Intermediate---Range, Lockup Drive, No Steer---Schematic View INTERMEDIATE---RANGE CLUTCH APPLIED LOCKUP CLUTCH APPLIED DIRECTION OF TRAVEL