6.6L Duramax L5P TCM Tuning Upgrade Kit | GMC/Chevy 2017-2023

Overview

This TCM tuning bundle gives your 2017–2023 L5P GM Duramax a new unlocked Transmission Control Module paired with an advanced TCM tune file and OBD2 tuning credits. The included L5P TCM calibration rewrites shift schedules, shift points, torque converter lock-up settings and transmission line pressure — a complete TCM upgrade for trucks that need transmission behavior to match a modified powertrain.

Compatibility

• Years: 2017–2023
• Makes: Chevrolet Silverado, GMC Sierra
• Models: 2500, 3500
• Engine: 6.6L Duramax L5P Diesel only

Kit Components

• Unlocked TCM — T87A for 2017–2019; T93 for 2020–2023. Select your model year before adding to cart.
• GM Duramax L5P TCM Tune File — Year-matched calibration file included with the TCM.
• 4x OBD2 Tuning Credits — Required to flash the tune via your OBD2 interface.

Not Included: GM Duramax L5P OBD2 Flash Delete Tuning Interface. Purchase separately, or get it inside the All-In-One DPF/DEF/EGR Delete Kit. Already own one? Provide your serial number at checkout to register the included credits.

Technical Specifications

Key Features & Build Details

• Unlocked TCM Hardware — Ships as a new unlocked unit matched to your model year. The T87A covers 2017–2019 trucks on both 6-speed and 10-speed transmissions. The T93 is its successor for 2020–2023 diesel L5P applications.
• Revamped Shift Schedules — The tune file rebuilds factory shift scheduling to better suit real-world diesel load demands.
• Modified Shift Points — Upshift and downshift thresholds are adjusted beyond factory settings.
• Finely-Tuned Shifts — Shift quality and timing are calibrated for consistent, predictable feel across operating conditions.
• Optimized Torque Converter Lock-Up — Lock-up parameters are revised to improve efficiency and reduce slip under load.
• Adjusted Transmission Line Pressure — Line pressure is recalibrated to reinforce clutch pack clamping under elevated torque conditions.

Installation Notes

A GM Duramax L5P OBD2 Flash Delete Tuning Interface is required to flash the included tune file — not included in this bundle. Purchase it separately or with the All-In-One DPF/DEF/EGR Delete Kit. Already own one? Have your serial number ready at checkout to register your 4 tuning credits.

Frequently Asked Questions

Q: Which TCM ships for a 2017–2019 L5P truck?
A: The T87A unlocked TCM, optimized for both 6-speed and 10-speed transmissions. Select the 2017–2019 option at checkout.

Q: What is the T93 and how does it differ from the T87A?
A: The T93 is the successor to the T87A, designed for 2020–2023 L5P diesel applications.

Q: Does this bundle fit gas engine trucks?
A: No. This bundle is for L5P diesel applications only.

Q: Is the OBD2 flash interface included?
A: No. It must be purchased separately, or is included with the All-In-One DPF/DEF/EGR Delete Kit.

Q: I already own the OBD2 interface — how do I use the included credits?
A: Provide your interface serial number at checkout and the 4 credits will be registered to your device.

Q: Is this product refundable?
A: No. This is a final sale, non-refundable product. Confirm your year selection and verify you have the required OBD2 interface before ordering.