Or take it to any shop that has the tool... And honestly, you could replace what was bad and replace all the electronics. BUT, that is no guarantee it would fix it. Plus, the electronics are about $600, no including labor. It's smart just to get a low mileage transmission and take good care of it. Take it from someone who has been through all of this.
/ 2002 WJ 4.7 H.O. / Flowmaster 50 SUV / Magnaflow Cats / Rocking that 2WD! /