If I had to guess, that would be what I'd pick...the reason being is that it's right where a speedometer drive gear would fit, driven by the output shaft.

 

Depends on which one. the #1 speed sensor is a tiny reed switch in the gauge cluster behind the speedometer driven by the magnet on the end of the speedo cable. the #2 speed sensor is in the transmission and that may or may not be it (the rear-most wiring of the trans is for the ABS speed sensor-only used by the ABS.

 

Oh. I also have my speedo needle wobbling up and down around 10-30 mph. And in between the wobbling my trans shifts from 2nd to 3rd back and fourth until i give it little more gas to stay on 3rd and is normal from there on. I have code 61 for trans for #2 speed sensor in tranny