Uncle Loyd's 72' C-10

[TA_C10]

My PCM had the gear indicator configured from factory. It was actually from a 6.0 engine but minor differences from 5.3. The 4l60e neutral safety switch is attached to the gear drive so it reads what gear the vehicle is in therefore translating that data to the PCM. If you install that neutral safety switch on your trans(even if you use the neutral safety on your column instead, this is what sends the gear indicator signal. I can't imagine a PCM not being setup to read gear indicator in your setup as mine is an older GEN III