I came across the same problem with a 91 chevy pickup. Its an easy fix. Pull the 4 bolts on the rear housing on both trans. Once removed you will notice the mechanical gear is plastic and the electronic is steel. Just swap the two around and you're good to go. The only bad part is finding a large enough puller for the steel gear. Remember to reset the detent cable once the new trans is in. If not you could burn up a new trans. Oh, keep the rear housing together with the steel gear so you can bolt on the torque arm. Sorry if this gets to you late.