what could it be???????????

:bang: hey guys, i need help, i have a 89 lx, 5.0 with a auto tranny, when im in overdrive and kick it down the tac redlines like the tranny is slipping, but in first i can hold the brake and give it gas and it will smoke the rear tires, no slipping at all, what could be wrong, a bad filter in the tranny maybe?:bang: :bang: :bang: :bang: