Multiple problems Help

1998 Dodge Caravan, 186,500 Miles, just had a transmission put in it, the last one kicked and bucked and did not go through the range of shifting. Now the Car the check engine light comes on interminntly and the ABS light as well, the cluster goes dead at times yet all the equipment works, A couple of years ago, the ignition switch went faulty and a locksmith did something to the tumblers in the switch. Since then the door chimes with or w/o the keys in with the driver side door. Prior to the Transmission going out, I put a new Battery in it. And wonder if the green flacky stuf with the cables mgiht have something to do with all these problems. Its the wife's car. And frankly I want my 4Runner back! I don't know where to start to look or try to repair!