1999 Auto Cavy shift prob

I have a 1999 and when i go to shift into drive it stalls. Reverse and nuetral all work but only when i try to shift it into drive it stalls. when i unplug the transmission plug in in front it will shift into drive but it wont shift right when i'm going down the road..i've replaced the whole tranny, the torque converter, the computer, the nuetral safety switch...what else could it be??? any info would be great