The Chrysler A-604 Ultradrive 4-Speed Automatic Transaxle

A new kind of four-speed automatic transaxle, engineered from concept specifically for real-time closed-loop electronic control, has been designed, developed, and put into production by Chrysler Motors Corporation. This overdrive transaxle combines two simple planetary gear sets with five disc-clutches, five hydraulic spool valves, and four direct-acting three-way solenoid valves to achieve all operating modes. It uses no bands and only the torque converter stator has a freewheel element. It provides both a fourth ratio and increased engine torque capacity in the same package space used by the previous three-speed transaxle. At the same time, fewer parts are required and manufacturing is more readily automated.