Transmission kicks and AC stops cooling ELECTRICAL PROBLEMS

I have a 98 Aurora that the transmission starts kicking when going from
P to D and It will not change gears. Also the AC stops cooling. It does not happen all the time. Everytime it happens I have to stop the car a I guess the computer resets. Please help. You can emai me at [email protected] Do you think is a sensor? And Can I replace it? Where is it? Thanks

I'm taking a shot in the dark here so dont blame me if im wrong but i suspect the input speed sensor.