6.6L Duramax L5P TCM Tuning | Tune File or File + Credits | Chevy & GMC | 2017–2026
Type: All-in-one Kit | Fits: GM Duramax
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Improve shift behaviour and transmission response with JS Speed Diesel TCM tuning for your 6.6L Duramax L5P. Choose the tune file on its own or combine it with the credits needed to license your existing transmission controller.
Choose your tuning option
| Option | Included | SKU |
|---|---|---|
| Tune File + Credits | Vehicle-matched TCM tune file and 4 tuning credits | L5P-TCM-KIT |
| Tune File Only | TCM tune file; required licensing credits purchased separately | L5P-TCM-Tune |
Vehicle compatibility
- 2017–2026 Chevrolet Silverado and GMC Sierra 2500/3500 with the 6.6L Duramax L5P diesel engine.
- For tuning a compatible, functional existing T87A or T93 transmission controller.
- Provide your model year and vehicle details so the correct calibration can be supplied.
Features
- Revised shift schedules and shift points.
- Adjusted shift feel and transmission line pressure.
- Optimized torque-converter lock-up settings.
What you need
- A compatible MPVI3 or MPVI4 tuning interface, sold separately.
- The required controller licensing credits. Four credits are included with Tune File + Credits.
- Your interface serial number when purchasing credits.
Frequently asked questions
Does either option include a replacement TCM?
No. Both options supply tuning for your existing controller. A physical transmission control module is not included.
Which option includes credits?
Tune File + Credits includes four credits. Tune File Only does not include credits or a tuning interface.
Can I return a tuning file?
Custom tuning is final sale. Confirm vehicle and interface compatibility before ordering.
What information is needed before programming?
Supply the vehicle details and interface serial number. Follow the supplied programming instructions and maintain stable battery power during the flash.
Important Notes:
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Return Policies
Your satisfaction is important to us. If you wish to return an item or request a refund, please review the terms and conditions outlined in our Returns Policy.
Important Notices
- Off‑Road Use Only
Products sold by JS Speed are intended for off‑road use and may be illegal on public roads where emissions or pollution‑control laws apply. - Check Local Laws
Before purchasing or installing, verify all applicable local, state/provincial, and federal regulations to ensure the modification is legal in your area. - Professional Installation Recommended
These parts should be installed by qualified professional mechanics. Improper installation can cause performance issues or vehicle damage. Unless a product page explicitly states otherwise, installation instructions are not included. Components are designed for users with solid mechanical knowledge, and minor adjustments or modifications may be required for proper fitment. Returns or refunds cannot be accepted due to difficulty completing an installation or the absence of instructions. - Warranty Impact
Use of these parts may void your vehicle’s factory warranty. Confirm with your vehicle manufacturer before purchase and installation. - Limitation of Liability
JS Speed is not responsible for damage, failures, or issues arising from the use or installation of these products. - Product Images
Images are for illustration only and may differ from the actual product due to manufacturer updates or improvements. - No Performance Guarantees
While these products are designed to enhance performance, JS Speed does not guarantee specific performance results.
6.6L Duramax L5P TCM Tuning | Tune File or File + Credits | Chevy & GMC | 2017–2026
Vehicle Fitment
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