There was a 4L80 option on I believe, only the '91. With 4x4 it came with an NP205... AND the GM shift controller that I think piggybacked the
ECM or perhaps was stand alone? Anyway... THAT model is the Holy Grail.
They would have definitely had it in the computer, which goes from an ECM to a PCM with the added trans controls. It’s crazy how you have all the old style transmissions in 1990, the TH400, 700R4, 200-4R, 440-T4, and then almost everything goes electronic in almost every vehicle in 1991. All you had was the 700R4 holding out in lighter trucks till ‘92, and then it was gone after that, too. I guess it’s the winds of change, but
I’ve had good luck with all those transmissions named above, and they do everything their successors do without all the bullcrap minus the 4L80E. Although if GM would have wanted to build a beefy, hydraulically controlled four-speed OD auto, I’m sure they could have. Torqueflite did with the 47RH, and some would argue they can do better than a 4L80E. Ford, as usual, dropped the ball. I’m only half kidding, by if you tow seriously with that E4OD, Ford didn’t do any kind of added cooler, and some of the parts weaker on the earlier ones so expect to burn it.