The driven gear is held on to a shaft by a snap ring, and so to get it out I believe you would have to pull the transaxle and separate the front differential from the transmission. I say this because the gear is of a larger diameter than the sensor (just verified this with a few parts I have in a bin) and therefore couldn't be extracted while in-car. Sorry.
That said, the sensor that reads gear rotation can be removed by unscrewing it from the case.
I don't think it would be easy, but it might be possible to remove the sensor and turn the axles and see if the shaft is rotating - which would help you to know if one of the gears drive/driven was bad.