Electric Transmission is sending power from one point to another.
As for truck transmissions, there are NO electric transmissions, just electrically controlled transmissions (ie, autoshift). A computer actuates the clutch, and based on factors (rpm,load,etc) floats the trans in and out of the gears required, meaning the driver doesn't have to shift. There are also automatic transmissions, however they are mostly found on vocational trucks: Dumps, mixers, beer/pop delivery, etc.