Gooday mate!
Strange here I am an Aussie in NC...answering an Aussie in Royalla...and yes I know where that is...
On your 4l80e there are two holes on the US drivers side for input and output sensors.
The hole directly above the shifter linkage is the input sensor or turbine sensor. The other sensor hole located in the rear part of the case would be your output sensor.
Use this one for your speedo.
You can PM me if you need more help or just want to chat...
Aussie, Aussie, Aussie....