Mojojoejoe95

Okay so I recently picked up a 1988 s15. The guy I got it from said the transmission (5speed manual) in it came out of a newer s10 but he didn't know what year. The transmission has has a sensor and the original speedometer is cable driven. So my question is how can I connect the speedometer cable I have to the sensor on the transmission with out spending 400$ on that stupid box im seeing. I have found a 40$ dollar part that will do the reverse of what I need but I can't seem to find what I'm looking for. Any help is greatly appreciated.