Some of us don't like how the transmission shifts anyway.
A buddy and I did an engine swap that required a different ECU. Fortunately, it was a fairly primitive unit. We just added more sensors in addition to the ones used by the instrument cluster and whatever else. A resistor was added to the tachometer, the oil pressure sender needed to be swapped, a few wires on the harness needed to be shorted, one needed power, and the fuel pump needed a special wire added to it. Stupid things, really. We didn't care if it used the cold-start routine; it runs better with the normal routine anyway. Don't need that wire. Snip! Just faking signals that we don't need. Butt-simple. Runs like a champ and started on the first turn of the key. ...okay, maybe not the
first turn. Apparently the ECU's ground wire does not ground to the ECU's case, which
also needs to be grounded. But that fixed itself when the ECU fell behind the transmission bell-housing during the second turn of the key.
Anyway, my point is that most of the stuff the TCU expects to see can be faked, especially if nobody cares if the transmission holds third gear when the engine is cold or similar behavior - although even that signal can be faked with ease. I'm sure I'm not going to notice a difference in how the transmission shifts at 2500 feet above sea level. Snip!
I want to see somebody do this and beat the snot out of the newer transmission to see if it can take it. I'm curious to know what it takes to break the new slush-boxes. They've got that shift-tronc brain too, yes? Oooh! Oooh! Break it! Break it!