Hyundai Repair: 2001 Kia Optima P0720, vehicle speed sensor, brake master cylinder

Question
can you tell me where the speed sensors are located on the transmission and are the transmissions the same in the four and six cylinder models

Answer
While there may be some minor differences between the transmissions (such as final drive ratio) used in the four and six cylinder Optimas, their overal design, control, and operation is the same.  Externally, they'll appear the same.

There are three speed sensors on the transmission.

The input speed sensor is located on top of the transmission under the bracket that holds the shift cable in place.

The output speed sensor is located on the top of the transmission, toward the rear, and toward the left side of the car.  It's almost exactly under the front of the brake master cylinder.

The vehicle speed sensor is on top of the differential portion of the transmission.  This is at a lower level than the other two sensors, is toward the back of the transmission, and is near the engine end of the transmission.

In nearly all cases that code P0720 sets, the culprit is a defective output speed sensor.