I have a 1998 GMC Jimmy that won't automatically shift, the key gets stuck in the ignition, and the speedometer and tachometer die periodically. Sometimes the gauges come back but that doesn't make it shift. I can manually shift through all the gears while driving. I used an OBD2 Reader to the computer and got the following errors: P0740 (Torque Converter Clutch Circuit Malfunction) and P1860 (Manufacturer Specific DTC), P0753 (Shift Solenoid A Circuit Electrical), P0758 (Shift Solenoid B Circuit Electrical), and P0758 (Shift Timing Solenoid Malfunction). Someone previously replied to a similar thread that it could be a faulty ignition switch. Any further suggestions?