6.6L Duramax L5P Tuning Package | 2017-2026 GMC/Chevy

GM Duramax L5P Tuning Kit (2017-2026) is the tuning-only portion of our complete L5P delete solution — built for owners who already have their EGR delete hardware and exhaust sorted and just need the tuning side handled. This kit gives you everything required to unlock (where applicable), flash, and run custom Black Bandit SOTF or single-calibration tunes on your L5P without piecing together tuning hardware from multiple sources.

What's Included in the L5P Tuning Kit

Everything included is chosen to work together: the tuning interface with the correct number of credits for your year, the appropriate ECM tuning package for your platform, and optional TCM tuning for customers who want their transmission calibration matched to their engine tune. This kit does not include EGR/cooler delete hardware, CAN BUS plug kit, or exhaust — if you need those, check out our All-In-One Delete Kit or add the delete hardware separately.

• Power gain range: varies by tune and supporting mods
• Operating range: designed for race use; lower EGTs when properly calibrated
• Optional TCM tuning: available for 2017-2026 L5P applications using the existing T87A or T93 TCM

Note: If you have a late 2018 Duramax L5P and know the E41 ECM Unlock Tool isn't required for your vehicle, the 2019 variant does not include the Unlock Tool and will be fully compatible for the late 2018 Duramax L5P's.

Vehicle Compatibility

Year / ECM / TCM Notes

• 2017-2018: E41 ECM (Unlock Tool compatible)
• 2019-2023: E41 ECM (Unlock Tool supported with updated process)
• 2024-2026: E42 ECM — requires E42 service (not included in kit)
• 2017-2019: T87A TCM — existing TCM can be licensed and tuned directly
• 2020-2026: T93 TCM — existing TCM can be licensed and tuned directly

Select your year set during configuration: 2017, 2018-2019, 2020-2023 or 2024-2026

Fitment is year and ECM/TCM-specific, which is why you select your exact model range when ordering. 2017-2018 trucks use the E41 ECM and are fully compatible with the Unlock Tool process. 2019-2023 Duramax L5P trucks still run E41 hardware with an updated unlock procedure. 2024-2026 trucks use the newer E42 ECM platform and require external unlock service before tuning. Optional TCM tuning works with the existing T87A or T93 transmission controller depending on model year.

Customization Options

1. Year Selection: 2017-2018, 2019, 2020-2023, or 2024-2026 GM Sierra/Silverado 2500/3500 L5P Duramax.
2. TCM Tuning: Add TCM tuning to your ECM tune package to calibrate transmission shift strategy, shift points, torque converter lock-up, and line pressure.

Optional TCM Tuning

Add Black Bandit TCM tuning to your L5P tuning package to match the transmission calibration to your engine tune and supporting modifications. TCM tuning uses your existing transmission control module — no replacement hardware is required.

• 4 OBD2 credits included with the TCM tuning option
• Existing TCM: T87A or T93 depending on model year
• No TCM hardware upgrade required
• Vehicle licensing included
• Requires a compatible OBD2 Flash Tuning Interface

TCM calibration includes:

• Revamped Shift Schedules: Recalibrated shift scheduling to better suit modified diesel powertrains.
• Modified Shift Points: Upshift and downshift thresholds adjusted beyond factory settings.
• Finely-Tuned Shifts: Shift quality and timing calibrated for consistent, predictable operation.
• Optimized Torque Converter Lock-Up: Revised lock-up parameters to improve efficiency and reduce slip under load.
• Adjusted Transmission Line Pressure: Recalibrated line pressure to support clutch pack clamping under elevated torque conditions.

Features

• Pre-tune requirement: Always flash the calibration before making any hardware changes
• Unlock Tool Upgrade:
  • 2017-2018: Unlock Tool Upgrade included (No ECM replacement, immobilizer, or crank relearn)
  • 2024-2026: HP Tuners unlock service required (ECM's must be sent to HP Tuners to be unlocked before it can be tuned, service not included with this product)
• OBD2 Flash Delete Tuning Interface:
  • 4 credits for 2017-2023
  • 8 credits for 2024-2026
• 5-Level SOTF tuning package (2017-2023 only): 0HP / 50HP / 75HP / 100HP / 150HP Switch On The Fly
• 2024-2026 variant is a single calibration tune (no SOTF)
• Optional TCM Tuning: Available for 2017-2026 L5P applications and includes 4 OBD2 credits for flashing the TCM calibration
• Existing TCM: TCM tuning works with the factory T87A or T93 module; no hardware replacement is required

Benefits

• Power & torque: Optimized fueling delivers instant gains, especially when paired with supporting exhaust and delete mods
• Drivability: Smooth shifts and stronger mid-range with custom tunes
• Transmission performance: Optional TCM tuning adjusts shift strategy, shift points, torque converter lock-up, and line pressure to complement the engine calibration
• Simplicity: Unlock Tool Upgrade avoids ECM swaps and relearn steps
• Flexibility: Pairs with EGR delete hardware and exhaust you already have or are sourcing separately

Shipping & Tuning Details

• Lead times depend on year and configuration. 2024-2026 kits may require additional prep due to E42 service requirements.
• Review the installation instructions before beginning.
• Tuning and hardware setup are detailed processes. We appreciate your patience during order preparation.
• TCM tuning is delivered as an optional addition to the main ECM tuning package and requires the appropriate OBD2 tuning interface.

TCM Tuning FAQs

Q: Do I need to buy a new TCM?
A: No. The TCM tuning option works with your existing T87A (2017-2019) or T93 (2020-2026) TCM. No replacement module is required.

Q: What is the difference between T87A and T93?
A: The T87A is used in 2017-2019 L5P trucks and supports both 6-speed and 10-speed applications. The T93 is used in 2020-2026 L5P diesel applications with the 10-speed transmission.

Q: I have a T93 — do I need to purchase an upgrade?
A: No. The existing T93 can be licensed and tuned directly through the OBD2 interface.

Q: Does TCM tuning work with gas engine trucks?
A: No. The TCM tuning option is intended for GM 6.6L L5P Duramax diesel applications only.

Q: Is the OBD2 Flash Tuning Interface included with the TCM tuning option?
A: No. The OBD2 Flash Tuning Interface must be purchased separately unless it is already included with your tuning package or All-In-One DPF/DEF/EGR Delete Kit.

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

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

Q: What if I need a physical replacement TCM?
A: Contact us separately if your T87A or T93 TCM is damaged or defective. The TCM tuning option is intended for existing, functional transmission controllers.