Jeep Grand Cherokee Transmission Codes P0783 and P0740: Shift Issues Between 3rd and 4th Gear
My Jeep Grand Cherokee's transmission began exhibiting shifting problems yesterday — it will not shift from 3rd to 4th gear or into overdrive. The fault codes detected are P0783 (Shift Malfunction) and P0740 (Torque Converter). I'm currently considering replacing the 3-4 shift solenoid to see if that resolves the issue. However, I want to confirm whether this is a mechanical or electrical problem before proceeding with any repairs.
Have you used an OBD2 scanner instead of relying on the key-on-key-off trick? No other symptoms or recent maintenance work have been reported. Before performing a transmission rebuild, ensure that all solenoids (including TCC and 3-4) are inspected. These codes specifically relate to the electronic components of the 42RE transmission — such as the torque converter control and shift solenoids. It's worth checking the wiring harness and connections thoroughly, as some issues may not appear during a simple key-on-key-off cycle and could be missed without proper diagnostic tools.