L5P TCM Tuning Kit

The Spelab L5P Transmission TCM Tuning Kit is a transmission control module enhancement specifically engineered for 2017–2026 GMC and Chevy 6.6L Duramax trucks with L5P engines. This kit offers premium transmission calibrations, perfectly optimized to complement upgraded powertrains. It functions by licensing your factory TCM and uploading pre-built tune files, which recalibrate shift timing, shift points, torque converter lockup behavior, and transmission hydraulic line pressure. Key features include redesigned shift maps to accommodate heavy hauling and daily driving, custom shift point calibration to surpass OEM limits, and precisely calibrated shift timing for smooth, consistent gear changes. The torque converter lockup logic is revised to reduce slippage under load and improve fuel efficiency, while transmission line pressure is recalibrated for firmer clutch clamping to reliably handle increased torque output. This tuning package is fully compatible with stock T87A (2017–2019) and T93 (2020–2026) TCM units, requiring no additional hardware. An OBD2 Flash Tuning Interface is necessary to flash the tune file. This product is intended for off-road use only and is a final sale, non-refundable item. Compatibility is limited to L5P diesel applications and does not fit gas engine trucks. A Windows-based laptop is required for the tuning software.