Blown speed sensors?

My neigbhor has 02 optima. He ask me if I would change the speed sensor, because he heard a bang and then the check light came on and the code po 705 if i rember right came up. Speed sensor malfuntion. I changed the sensor for him. 1 day later bang it's back. Same thing, plus it did't shift right and no power i was told by his girlfriend. He and i took it out for a drive alittle later after it cooled alittle and shifted fine with the code still there from the 2nd time. Is the tran fluid bad. Tranny shot? I'm stumped.

My neigbhor has 02 optima. He ask me if I would change the speed sensor, because he heard a bang and then the check light came on and the code po 705 if i rember right came up. Speed sensor malfuntion. I changed the sensor for him. 1 day later bang it's back. Same thing, plus it did't shift right and no power i was told by his girlfriend. He and i took it out for a drive alittle later after it cooled alittle and shifted fine with the code still there from the 2nd time. Is the tran fluid bad. Tranny shot? I'm stumped.

I believe you have a code for a range sensor not a speed sensor. Also there are 3 speed sensors on a KIA trans input turbine speed, output turbine speed and vehicle speed sensors.

Judging by the year and potential mileage of the vehicle if the trans fluid has not been changed at regular intervals it is more than likely you have a trans. internal problem.

I would check the color and condition of the fluid it should be reddish in color not brown or black. If it is dark I would take it to a KIA dealer or a reputable transmission repair facility.