This is the first chance I have had to see this but what year is your car??? If you have a 98 or newer GT then you have a 4T65E. The 440T4 wasnt used after the 91-93 era depending on model so at best it would be a 4T60E and only if a 97 GT. Either way neither of those earlier transmissions had pcm controlled line pressure and that was only on the 4T65E between all the above three transmissions. Glad it worked out of its bug, like everyone else mentioned it probably just needed reset and had learned to a worn trans in its previous car. Sometimes the pressure control solenoid will be stuck or the pcm sees an issue and commands max line pressure until reset. The more you drive the car in all conditions the faster it learns, often the shifts start soft and firm up the more you drive the car just as you have noticed so far.