ok i just fixed the speed sensor on my 99 kia sephia ls! ok ummmm.... here's wat i did... i removed the air filter assembly just the the large rubber hose between the throttle body and the actual air filter. It's held by a those screw clamps on each end. It's #4 in pic below!
After that's removed its easier to get to the actual sensor. it's left of the trannmission dipstick in the rear of the tranny itself. It's right above the catylitic converter if i'm not mistaken.
You need a 10mm socket wrench, and keep in mind back there is kinda tight. i remove the negative battery cable to reset the OBD and also to be on the safe side when i deal with any electrical components
Remove the clip attached the speed sensor. Remove the 10mm bolt and pull upward to remove the sensor. Then you should compare them to the one you have to see if it's the same fitting one.
this is a pic for an Manual Trans Speed sensor
Auto Speed sensor comparison new(right) old ( left)
notice the spacing between the red spinner thing, the washer and the housing itself
Try not to work around heavy debris area b/c the this sensor is sits in tranny fluid and you dont want any unwanted particles inside your Tranny.
Replace the sensor with the new one, mines was a little tight but it fit. try to place it in as far as possible in and then the screw will take care of the rest. Once its in screw it back down, attach the clip, replace the air filter assembly. Hope this helps!