Here is a very brief description: P0742 Torque Converter Clutch Circuit Stuck On
This is an internal transmission issue that is going to require some investigation by a qualified technician. They should check for any technical info from Chrysler first (recalls, technical service bulletins etc) and then perform the appropriate troubleshooting for the P0742 code. Expect to have them start with a 1-2 hours diagnosis time to look at this. - Bret Bodas
The result of the diagnosis will tell you that, the worst case scenario is you need a transmission. Best case it may be fixed for a couple hundred dollars.
You have to take into consideration what the vehicle is worth fixed and broken, and how much you will spend to get another vehicle. Take into account all the other expenses of getting another car as well, loan payments, insurance, fuel economy etc. - Bret Bodas