Check the speedometer driven gear (around $20 from the dealer) on the end of
the sensor, located on the passenger side of transmission, just ahead of the
u-joint. Look for the wiring harness connection, and remove the 10mm bolt
holding the sensor. Pull the unit out, and you'll see the nylon gear at the
end which is probably missing a few teeth. Just replace the gear, not the
whole sensor. Takes about 10 minutes to do.