I've used that method also and the Alli learns real fast. Maybe Mike L could tell us more..... good idea or not?Straight for the Diablosport website:
"Your vehicle is equipped with an Allison Transmission. This Transmission has a learning process to compensate for the type of driving the user does. This process is learned by bringing the vehicle up to 55 mph and then put it manually into first gear. The transmission will then automatically down shift itself through all the gears to down to first, and when you stop put it in park and shut the car off. Repeat this process three times. This lets the transmission learn how to deal with the extra power given to it by the predator."
"The Predator for Duramax truck has no transmission function in it at all. No manufacturers can communicate directly with the Allison transmission. It is a self-learning system, the trick is to drive it, and it will adjust to the power level your using in time. The more you change around the power level the longer you drag it out, the higher power levels will adapt for the lower ones, and the harder you drive it the faster it will adapt.
Now there is also kind of a trick you can play on the system that helps speed up the process. Take the truck out on an open piece of road, allow it to shift all the way up to high gear at cruise, then release the throttle and shift the truck down into low gear, not to worry it will not jerk down into low gear, foot off the throttle allow the vehicle to shift down through the gear progression until your riding along in low, apply brake, put the truck in Park, and do it again.
After two or three times, generally, you will see improvements right away, Allison has learned.
Or just keep driving and it will improve on its own, just know your going to have to wait it out.
Again this is the case for every manufacturer adding horsepower to the GM Duramax trucks."
I can attest to this working just as DiabloSport states.