TORQUE CONVERTER AS 6Y6778 - Caterpillar

When the pilot valve is placed in the FLOAT position, pilot oil for lowering the work tool (E) moves the lift spool (32) to the FLOAT position. The pilot valve is detented in the FLOAT position. The control valve will remain in this position until the pilot valve is pulled out of the detent.When the control valve is in the FLOAT position, the weight of the work tool and the lift arms will cause the work tool to lower to the ground. Both ends of the cylinders are open to the tank. The work tool will then follow along the contour of the ground because the head ends and the rod ends of the lift cylinders (3) are equal in pressure.When the lift spool (32) is in the FLOAT position, oil from the gear pump (P) can flow through the lift spool to the tilt control valve.Tilting the Work Tool Backward
Illustration 35 g00603939
(1) Auxiliary lines. (2) Tilt cylinders. (3) Lift cylinders. (4) Bank valve. (33) Tilt spool in the TILT BACK position. (A) Pilot oil for retracting the tilt cylinders. (B) Pilot oil for raising the work tool. (E) Pilot oil for lowering the work tool. (F) Pilot oil for extending the tilt cylinders. (G) Pilot oil for sending oil to the bottom connection. (H) Pilot oil for sending oil to the top connection. (N) Oil that goes back to the diverter valve. (O) Oil that goes to the ball valve. (P) Oil that comes from the gear pump. (Q) Oil that is returning to the tank.When the pilot oil for retracting the tilt cylinders (A) moves the tilt spool (33), oil from the gear pump (P) flows into the bank valve (4) and to the rod ends of the tilt cylinders (2). From the head ends of the tilt cylinders, the oil flows out of the bank valve and to the tank. The diverter valve (if equipped) does not affect the operation of the tilt cylinders when the lift spool is in the HOLD position.Tilting the Work Tool Forward
Illustration 36 g00603956
(1) Auxiliary lines. (2) Tilt cylinders. (3) Lift cylinders. (4) Bank valve. (33) Tilt spool in the TILT FORWARD position. (A) Pilot oil for retracting the tilt cylinders. (B) Pilot oil for raising the work tool. (E) Pilot oil for lowering the work tool. (F) Pilot oil for extending the tilt cylinders. (G) Pilot oil for sending oil to the bottom connection. (H) Pilot oil for sending oil to the top connection. (N) Oil that goes back to the diverter valve. (O) Oil that goes to the ball valve. (P) Oil that comes from the gear pump. (Q) Oil that is returning to the tank.When the pilot oil for extending the tilt cylinders (F) moves the tilt spool (33), oil from the gear pump (P) flows into the bank valve (4) and to the head ends of the tilt cylinders (2). The oil from the rod end of the cylinders flows to the valve spool. The oil flows through