I am doing an 80 chev 4x4 with a GM Perf LS3 and a GM Perf 4L70E with a 205 transfer case.

The trans controller that came from GM Perf says that a TISS (Transmission Input Speed Sensor) is not required to be connected for 4L6x and 4L70 trans it is only required for a 4L80. It does show an OSS (Output Speed Sensor) for all 4Lxx trans. Is the OSS the VSS for trans shift control? What is the deal with the ISS, what is it used for on the 4L80.

Next challenge is the 4L70 is being adapted to the TCase an adapter housing which has a sensor it it but the tailshaft has no reluctor ring on it. And the TCase being out of the 80 Chev 4x4 has no electronic speed output only a cable for the speedometer. In a 4x4 where should the VSS signal come from the output of the trans or the output of the TCase. How is VSS dealt with when the TCase is in Hi vs Lo.

Thanks