[RichLockyer]

Sending unit is in the tranny.
To install the Speedo Healer, you remove the shift levers, loosen the front floorboard bolt, remove the rear, and drop the floorboard.
4 bolts in the side cover release that exposing all kinds of goodies you should familiarize yourself with, including your stator cover, the bevel gear housing, and the clutch slave cylinder (like brakes, it should be bled/fluid replaced every year or two).

Above the bevel gear housing you'll see a wiring harness with a triangular connector. That is the connector for the speed sensor. The Speedo Healer plugs in between the factory connectors. You can mount the Speedo Healer under the left side cover above your toolbox for easy access to programming.