I've never drove an automatic car, where from the factory.. you are allowed to change auto transmission parameters.Originally Posted by Jin
You can change shift points if you buy an external aftermarket tuner/programmer (SuperChips), but 9 times out of 10 you can't access any settings inside the TCM (Transmission Control Module) without an aftermarket accessory.
The way an automatic transmission works is one of the things you really don't want to give end-users a chance to change things.
One wrong setting can cause extensive wear on the transmission.. and if that car is still under a factory warranty.. then the company would have to assume service of it and replace it.
So they save the hassle and don't let you mess with things.