Transmission Harness
Swapping from a manual to an automatic transmission in your heavy-duty truck requires a complete electronic interface—the factory wiring lacks the necessary TCU-to-chassis connections for proper shifting, dash communication, and ABS integration. Kustom Truck Parts offers conversion-specific transmission harness kits tailored for Allison (WTEC III and Gen4) and Eaton (Autoshift/Ultrashift Plus/manual) systems in Kenworth and Peterbilt chassis with NAMUX1–NAMUX4 electronics.
Our kits provide the full electrical solution for seamless swaps:
- Allison Gen4 Harnesses: Include transmission-to-cab, cab-to-TCU, dash interface, power, and interconnects.
- Allison WTEC III Harnesses: For older electronic Allison conversions.
- Eaton Autoshift/Ultrashift Plus Harnesses: For automated manual conversions.
- Eaton Manual Harness: For Paccar engine replacements in Kenworth NAMUX3 trucks
- NAMUX4 VSS Extension: For Paccar engine replacements in Peterbilt and Kenworth NAMUX4 trucks—for vehicle speed sensor compatibility.
These harnesses ensure reliable TCU communication, accurate shifting, dash readouts, and ABS function as if factory-installed—eliminating codes and integration headaches in drivetrain repowers.
Browse below for your chassis, NAMUX generation, and transmission type. Pair with our clutch linkage kits, shift lever kits, or engine harnesses for a complete conversion. Need help confirming NAMUX compatibility or kit components? Contact our team for expert guidance.
