P0700 and P1776 Fault Codes on 2002 Chrysler Intrepid 3.5L: Transmission Control System Malfunction and Solenoid Issue

I recently purchased a 2002 Chrysler Intrepid with a 3.5L engine, and now it's displaying a P0700 diagnostic trouble code, which indicates a 'Transmission Control System Malfunction'. This is accompanied by a P1776 code, researched to mean 'Solenoid Switch Valve Latched in the LR Position'. In addition to these fault codes, I'm experiencing noticeable driving symptoms: when decelerating to 40 km/h, the vehicle lurches as if manually shifted into a lower gear—something that doesn't align with engine RPMs or normal downshift behavior. After this event, the car fails to upshift properly; at speeds of 100 km/h, the engine runs at an unusually high 4200 rpm. The issue resolves only after a complete shutdown and restart, but this fix is temporary—typically requiring 4 to 5 such resets within a 15-minute drive. I'm trying to determine the most likely root cause and repair options. Given that the vehicle is valued at around $3,000, I want to know whether fixing these transmission issues would be worth the cost of parts, labor, and potential long-term reliability concerns.