I have a 67 Cutlass with a LY6/4L85 trans. The trans upshifts fine, except to 4th or OD. I had a friend who does tuning, but not troubleshooting, hook up his laptop and using HP Tuner, was able to upshift and downshift to and from OD from the laptop. One of the screens or windows showed "No MPH", which he said would cause it not to shift.
I have an electronic Autometer speedometer that reads fine, so there is apparently a VSS signal from the trans. Another window shows that the ECM is "set" to an auto trans.
I have checked the brake light switch, it has 12 volts and functions apparently fine. Needless to say, I have little to no expertise on this. I have attached a screenshot of the transmission settings, but I don't know what I am looking at or for... I also have the complete HP Tuner files of my operating system.
I forgot to mention that a couple years back I had the car at a shop for some work, including a tune. They changed out the ECM/TCM as they were different models. I trailered the car home, and it basically sat for 2 years before driving it.
Any ideas, or where to look?

Thanks!!!

I should add that there are no codes stored, and all fuses are good.

 

So this was a working swap at one point, and you just lost OD at some point? Everything else shifts fine? Do you have both VSS's on this? Perhaps one of them went bad?

 

He says the speed works fine. Wouldn't That mean the vss is working?