Four speed ratio automatic power transmission

摘要

A manual valve alternately connects a source of regulated line pressure to a forward drive passage and to a reverse drive passage. A shift valve alternately connects these passages to an input port of a coast clutch valve in accordance with the state of a solenoid-operated valve. A control port of the coast clutch shift valve is pressurized either from a manual valve, when the gear is selected manually by the vehicle operator, or from the source of variable pressure control by operation of a variable force solenoid. In accordance with the control pressure, the coast clutch shift valve either connects its input to a line connected to the coast clutch (72) or vents the input to a drain passage in the shift valve.