[tininjun67]

""Unlike a 4L80 which must be manually shifted in & out of OD"
the 4l80 does not have to be shifted manually. It is run by a controller of your choice, which is programmable as to when you want gear changes to occur, including od. In order to engage the electronic trans brake, however, it must be manually shifted into
1st gear. (this option available with some shift kits) I shift my 4l80 into drive, then operate it with a series of switches. It looks like a hand held electric version of a lenco. No computer required.
I've personally watched a slightly modified (no new hard parts) 4l80e live behind an 830hp motor in a 4200lb car during drag racing, road courses, auto crossing and long trips without issue.