brunokc:
okay i need to go fast.
but there must be a way to get i to work a still be fast... i hope.
The wait time needn't be huge. You think the buttons are pressed at the same time, the controller knows differently. You at least need to allow loop() to whiz round a bunch of times to see each time if the second button is pressed, before it decides to shift.
Have you thought of a third, "go to neutral", button? Way simpler.