My 2017 579 Peterbilt, equipped with an ISX15 engine and a 16-speed Eaton automated transmission, recently developed a transmission problem. The truck currently has 807,000 miles. Initially, upon restarting the truck, the transmission light on the gear selector would flash, the dash alternated between “F” and “N,” and the engine wouldn’t start.
Replacing and recalibrating the Electronic Control Actuator (ECA) didn’t resolve the issue. The shop then addressed the starting problem by reloading relays and possibly replacing the wiring harness. After this repair, I drove approximately 6,000 miles without incident.
However, after a recent fuel stop, the transmission began beeping and flashing “N.” It wouldn’t engage in 3rd gear or any lower gear. Reverse was the only functional gear. Attempting to shift into Drive resulted in a spinning sound without engaging the gear. After restarting the truck, it displayed “F” on the transmission with a flashing service light, but surprisingly, it shifted into gear. I was able to drive, but the transmission wouldn’t shift beyond 10th gear, accompanied by continuous beeping.
Online research suggests potential causes could include faulty wiring, a blown 40-amp fuse related to the Gen1 ECA, or incorrect voltage readings to the ECA. I attempted to clear the codes by cycling the ignition switch six times, but the transmission remained stuck in 10th gear. The flashing “F” and service light on the gear selector are no longer present.
Currently at a rest stop in Wisconsin, I plan to continue troubleshooting tomorrow. Has anyone encountered similar issues with a 2017 579 Peterbilt and found a solution? Any insights or suggestions would be greatly appreciated.
