After 4L80 swap on my H2 I wanna take a signal from it's speed sensor (not mainshaft speed, but second shaft) for a naviagation system (it will allow to trace the car while in tunnels using gyroscope, vehicle speed etc).

As 4L80 kit includes extra wiring to install, I can't understand which PIN in the ECU not recieves the signal from that speed sensor to connect to this pin directly.

Could anyone advise please what is the correct pin?