Transmission trouble

The transmission slips. It has the correct transmission fluid and it is on the full mark. I have changed out the fluid to new fluid. I use the red bottle that says Honda's only transmission fluid and it still slips. Right now it is stuck in first and second gear and I have to use the gear shift. I can not drive it in d4 and drive it. I have to put it in first then d3 or d4 just to get it in second gear. It will not go into third or fourth gear. What should I do?