Both of these are listed as Vehicles Speed Sensor compatible with 93 Dakota v6 3.9.
Yet they look different and one is $90 and one is $13. I am confused. Need some help.

http://www.oreillyauto.com/site/c/de...1879&ppt=C0033



http://www.oreillyauto.com/site/c/de...1879&ppt=C0033

 

The first one listed is in the tranny. The second one listed is on the top passenger side of the rear diff.

 

Yes correct.

To go into a little more depth.
The 1st one is the Vehicle speed sensor which gives the PCM the Vehicle speed.
The 2nd is the ABS (Anti-Lock Brake System) wheel speed sensor, which is for the ABS system only. The links you posted states the names of the sensors.

I'm assuming your having problems with OD or something which you will need to replace the Vehicle speed sensor.

 

Thanks guys. I kind of knew that, but NOW it says ABS. Click on this and it says vehicle speed sensor, and even after you click on the Dormn one it still doesn't say abs, just Vehicle speed sensor. Just to let you know I wasn't crazy lol.

http://www.oreillyauto.com/site/c/se...1879&ppt=C0033