TCM Tuning Kit

The Spelab L5P Transmission (TCM) Tuning Kit provides premium transmission calibrations for 2017–2026 GM Duramax L5P trucks, specifically optimized to complement upgraded powertrains. This package recalibrates critical transmission functions including shift timing, shift points, torque converter lockup behavior, and transmission hydraulic line pressure. The system is designed to work with your existing factory T87A (2017–2019) or T93 (2020–2026) TCM units, requiring no additional hardware. Key features include redesigned shift maps tailored for heavy diesel hauling and daily driving, custom shift point calibration that raises or lowers trigger points beyond OEM limits, and precisely calibrated shift timing for smooth, consistent gear changes. The kit also offers optimized torque converter lockup logic to reduce slippage under load and improve fuel efficiency, along with recalibrated transmission line pressure for firmer clutch clamping to reliably handle increased torque output. This tuning package is intended for off-road use only and is a final sale, non-refundable product. Compatibility is limited to 2017-2026 Chevrolet Silverado 2500/3500 and GMC Sierra 2500/3500 models equipped with the 6.6L L5P Duramax diesel engine. A specific OBD2 Flash Tuning Interface is required for installation, and the system is only compatible with MPVI3 or MPVI4 tuners. The tuning process involves licensing your factory TCM and uploading pre-built tune files.