A 2010 4.8L V8 4WD vehicle with a 4L60e transmission recently experienced rough shifting and a Malfunction Indicator Lamp (MIL) code after a routine transmission service at 105,000 miles. The service included a fluid flush, filter replacement, and new ATF. The error code, identified as P2764, points to a potential issue within the torque converter clutch (TCC) system. This article will explore the symptoms, possible causes, and troubleshooting steps related to the P2764 code.
Symptoms of the P2764 Code
The vehicle exhibited harsh shifting between Park and Reverse, Park and Drive, and between first and second gears. These symptoms were more pronounced when the transmission was cold. While shifting between second and third gear was also rough, it was less severe than the lower gears. Shifting between third and fourth gear remained smooth. The harsh shifting was exacerbated at low RPMs and light throttle, while heavier throttle application seemed to lessen the severity.
Possible Causes of the P2764 Code
The P2764 code specifically indicates a problem with the “Torque Converter Clutch (TCC) Solenoid Control Circuit/Open”. This suggests a potential electrical fault within the TCC solenoid’s control circuit. Several possibilities exist:
- TCC Solenoid Dislodged: The TCC solenoid may have been inadvertently dislodged or damaged during the transmission service, specifically when the pan was re-installed.
- Wiring Harness Issue: The wiring harness connecting to the TCC solenoid might have been pinched or damaged during the service, leading to a short circuit or open circuit.
- Faulty TCC Solenoid: While less likely given the timing of the issue, a malfunctioning TCC solenoid itself could be the root cause.
- Low Transmission Fluid Level: Although the fluid level was checked and found to be within the acceptable range, a slight drop below the recommended level can sometimes trigger TCC related issues. It’s worth double-checking the fluid level to ensure accuracy.
Troubleshooting the P2764 Code
Before taking further action, it’s recommended to have the code re-scanned to confirm it is indeed P2764. If confirmed, the following steps can be taken:
- Visual Inspection: Inspect the TCC solenoid and its wiring harness for any visible signs of damage, loose connections, or pinched wires. Pay close attention to the area around the transmission pan where it was recently removed and reinstalled.
- Check Fuses: Verify that the fuses related to the transmission control module (TCM) and TCC solenoid are intact. Consult the vehicle’s owner’s manual for the specific fuse locations.
- Test the TCC Solenoid: Use a multimeter to test the resistance of the TCC solenoid and ensure it falls within the manufacturer’s specifications. This will help determine if the solenoid itself is faulty.
- Check Wiring Continuity: Test the continuity of the wiring harness between the TCC solenoid and the TCM to rule out any open circuits or shorts.
Conclusion
The P2764 error code, coupled with the described symptoms, strongly suggests a problem within the TCC system, likely related to the recent transmission service. While a dislodged or damaged TCC solenoid or wiring harness are the most probable causes, other possibilities should be investigated. A thorough inspection, followed by systematic testing of the TCC solenoid, wiring harness, and related components, is crucial for accurate diagnosis and repair. Consulting with a qualified transmission specialist is recommended if the issue persists.
