The torque converter both transmits and multiplies the torque from the engine using the ATF (Automatic Transaxle Fluid) into the transaxle (planetary gear unit) as the medium.
The torque converter consists of the pump impeller, turbine runner, one-way clutch and stator, and the converter case which contains all of these components. The converter is filled with the ATF, which is supplied by the oil pump. The engine rotates and the pump impeller rotates, then this fluid is forced out from the pump impeller in a powerful stream that rotates the turbine runner.
For ATF, DEXRON