ive never seen the wiper trans in a grand prix, but don't the wiper motor just have a L bracket bolted onto it and the trans arm gets snapped onto it?
that's the way most of my cars that i have replaced the wiper motor or trans worked.
if so hook it all up, and just turn the switch to off, and put on the wiper arms, in the down position, then run the wipers and see what happens. that's all i did on the last gm car i worked on. you may need to adjust them a little bit as to how far the blades are going to the driver side edge of the windshield, it may go past the glass. just remove the arm and turn it 2 or 3 splines the opposite way of the problem till your happy.
