ok i trans is messed up again and ideas wat could be wrong with it here's what it is doing

i drive out the road and it shifts very nice like it should .then when i stop at i red light and go to drive away from te light it shifts fine into second but when it go's to shift into drive itstart to slip real bad . so i pulled over and turned the car off . then the start off again and it works fine . this happens everytime i stop at a red light

any ideas would be helpful


thanks
jason