I expect OP already knows the best way to repair cars is to use a well recommended shop who has the experience, expertise, facilities, and equipment to do it correctly. If you want to diy’er fix this OP, suggest you focus on one problem at a time. Find out what the jerry rig was to get it to shift out of Park, and fix that right proper. A common reason you can’t shift out of Park is b/c the brake pedal interlock isn’t working correctly. That’s a safety mechanism used to prevent children left in the car from accidentally driving the car through the 7-11 plate glass window when the parents go inside for a big gulp. You have to press on the brake to get it to shift out of Park. That could be something simple, like the brake pedal part of that gadget needs adjustment.