In drive 1, transaxle drive is via the input shaft to clutch B. The elements of this transaxle function are as follows:
| • | Clutch B is engaged to drive the rear sun gear. |
| • | The rear sun gear drives the front planetary gear carrier clockwise. |
| • | The rear planetary gear carrier drives the front ring gear and front planetary gear carrier clockwise. |
Clutch B Engaged
In park and neutral solenoid valves 1 and 2 are both ON. Pressure control solenoids (PCS) 4 and 6 are also turned ON.
When PCS 6 is ON, the fluid supplied from the reduction valve flows to the safety valve, clutch valve B, and holding valve B. The oil that is supplied to the inlet port of the clutch valve presses on the valve spool. Line pressure then flows to the holding valve and check ball, engaging clutch B.
Clutch F Engaged
PCS 5 will be switched ON. The line pressure, which passed through the reduction valve, will flow to the holding valve and the clutch valve inlet. As a result the valve spool is depressed.
Lock-up Clutch
Solenoid 2 is turned ON and the line pressure control valve spool will be depressed. Fluid will now flow through the torque converter pressure valve.
As a result, the oil pressure behind the converter lock-up clutch piston and in the turbine zone is equal. The direction of flow is through the turbine shaft and through the space behind the piston, to the turbine chamber.
Lubrication/Cooling
The lubricating valve ensures that the converter is supplied with cooling oil first if the pump rate is low. The lubricating pressure valve in addition guarantees that the necessary amount of cooling and lubricating oil is available via the bypass duct.
As a result, the oil pressure behind the converter lock-up clutch piston and in the turbine zone is equal. The direction of flow is through the turbine shaft and through the space behind the piston, to the turbine chamber.
