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  • Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
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Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
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Load image into Gallery viewer, Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Load image into Gallery viewer, Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Load image into Gallery viewer, Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
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Load image into Gallery viewer, Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Load image into Gallery viewer, Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Load image into Gallery viewer, Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit

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Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit

Mishimoto
misMMTC-L5P-TBV
Out of stock
$166.99
The Mishimoto thermal bypass valve kit is specifically designed for your 2017-2019 Chevrolet Silverado and GMC...
Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
Description

The Mishimoto thermal bypass valve kit is specifically designed for your 2017-2019 Chevrolet Silverado and GMC Sierra 2500HD/3500HD with the 6.6L Duramax L5P engine. This upgrade enhances the efficiency of your truck's transmission cooling system by replacing the stock in-line thermal bypass valve, which is prone to failure and can lead to overheating. Crafted from durable CNC-machined billet aluminum, this kit not only provides superior strength but also features a sleek black anodized finish that resists corrosion and wear. Proper cooling is critical for maintaining transmission health, especially during heavy towing or demanding driving conditions, and Mishimoto’s design ensures optimal fluid flow and heat dissipation through strategically machined internal passages and cooling fins. The fully serviceable thermostat included allows for rapid warm-up in cold climates, while the optional bypass can be installed for constant cooling in warm weather or extreme conditions. This versatile kit is engineered for easy installation in less than an hour, making it a practical upgrade for your Duramax-powered truck. With Mishimoto’s commitment to quality and performance, this thermal bypass valve kit is built to last a lifetime, backed by the Mishimoto Lifetime Warranty, ensuring peace of mind on every drive.

Features:

  • Durable CNC-machined billet aluminum construction for longevity and strength
  • Eliminates failure-prone stock bypass valve to prevent overheating
  • Improves fluid flow and heat dissipation with strategically machined internal passages and cooling fins
  • Includes a fully serviceable thermostat for fast cold-weather warm-up
  • Optional thermostat bypass for continuous cooling in hot climates or towing conditions
  • Easy installation in less than 1 hour, designed for a perfect fit on 2017-2019 Chevrolet Silverado and GMC Sierra 2500HD/3500HD with 6.6L Duramax L5P engine
  • Finished with a corrosion-resistant black anodized coating and backed by Mishimoto’s lifetime warranty

Fitment:
2017 Chevrolet Silverado 2500 HD High Country
2017 Chevrolet Silverado 2500 HD LT
2017 Chevrolet Silverado 2500 HD LTZ
2017 Chevrolet Silverado 2500 HD WT
2017 Chevrolet Silverado 3500 HD High Country
2017 Chevrolet Silverado 3500 HD LT
2017 Chevrolet Silverado 3500 HD LTZ
2017 Chevrolet Silverado 3500 HD WT
2017 GMC Sierra 2500 HD Base
2017 GMC Sierra 2500 HD Denali
2017 GMC Sierra 2500 HD SLE
2017 GMC Sierra 2500 HD SLT
2017 GMC Sierra 3500 HD Base
2017 GMC Sierra 3500 HD Denali
2017 GMC Sierra 3500 HD SLE
2017 GMC Sierra 3500 HD SLT
2018 Chevrolet Silverado 2500 HD High Country
2018 Chevrolet Silverado 2500 HD LT
2018 Chevrolet Silverado 2500 HD LTZ
2018 Chevrolet Silverado 2500 HD WT
2018 Chevrolet Silverado 3500 HD High Country
2018 Chevrolet Silverado 3500 HD LT
2018 Chevrolet Silverado 3500 HD LTZ
2018 Chevrolet Silverado 3500 HD WT
2018 GMC Sierra 2500 HD Base
2018 GMC Sierra 2500 HD Denali
2018 GMC Sierra 2500 HD SLE
2018 GMC Sierra 2500 HD SLT
2018 GMC Sierra 3500 HD Base
2018 GMC Sierra 3500 HD Denali
2018 GMC Sierra 3500 HD SLE
2018 GMC Sierra 3500 HD SLT
2019 Chevrolet Silverado 2500 HD High Country
2019 Chevrolet Silverado 2500 HD LT
2019 Chevrolet Silverado 2500 HD LTZ
2019 Chevrolet Silverado 2500 HD WT
2019 Chevrolet Silverado 3500 HD High Country
2019 Chevrolet Silverado 3500 HD LT
2019 Chevrolet Silverado 3500 HD LTZ
2019 Chevrolet Silverado 3500 HD WT
2019 GMC Sierra 2500 HD Base
2019 GMC Sierra 2500 HD Denali
2019 GMC Sierra 2500 HD SLE
2019 GMC Sierra 2500 HD SLT
2019 GMC Sierra 3500 HD Base
2019 GMC Sierra 3500 HD Denali
2019 GMC Sierra 3500 HD SLE
2019 GMC Sierra 3500 HD SLT
2020 Chevrolet Silverado 2500 HD High Country
2020 Chevrolet Silverado 2500 HD LT
2020 Chevrolet Silverado 2500 HD LTZ
2020 Chevrolet Silverado 2500 HD WT
2020 Chevrolet Silverado 3500 HD High Country
2020 Chevrolet Silverado 3500 HD LT
2020 Chevrolet Silverado 3500 HD LTZ
2020 Chevrolet Silverado 3500 HD WT
2020 GMC Sierra 2500 HD AT4
2020 GMC Sierra 2500 HD Base
2020 GMC Sierra 2500 HD Denali
2020 GMC Sierra 2500 HD SLE
2020 GMC Sierra 2500 HD SLT
2020 GMC Sierra 3500 HD AT4
2020 GMC Sierra 3500 HD Base
2020 GMC Sierra 3500 HD Denali
2020 GMC Sierra 3500 HD SLE
2020 GMC Sierra 3500 HD SLT
2021 Chevrolet Silverado 2500 HD Custom
2021 Chevrolet Silverado 2500 HD High Country
2021 Chevrolet Silverado 2500 HD LT
2021 Chevrolet Silverado 2500 HD LTZ
2021 Chevrolet Silverado 2500 HD WT
2021 Chevrolet Silverado 3500 HD High Country
2021 Chevrolet Silverado 3500 HD LT
2021 Chevrolet Silverado 3500 HD LTZ
2021 Chevrolet Silverado 3500 HD WT
2021 GMC Sierra 2500 HD AT4
2021 GMC Sierra 2500 HD Base
2021 GMC Sierra 2500 HD Denali
2021 GMC Sierra 2500 HD SLE
2021 GMC Sierra 2500 HD SLT
2021 GMC Sierra 3500 HD AT4
2021 GMC Sierra 3500 HD Base
2021 GMC Sierra 3500 HD Denali
2021 GMC Sierra 3500 HD SLE
2021 GMC Sierra 3500 HD SLT

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You must report any missing or damaged items within 14 days of delivery.
After this time, we cannot be held responsible for lost or damaged items.

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You have 30 days from the date of delivery to request a return.
After 30 days, we are unable to accept returns, exchanges, or refund requests.

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Items must be returned in their original condition—unused, unwashed, and with all tags and packaging intact.
Certain products may not be eligible for return (e.g., special-order items, customized products, or perishable goods).
Items that have been altered, installed, or modified cannot be returned.

Return Process
Contact our Customer Support team to request a Return Authorization (RMA) before sending items back.
Once your return is approved, you’ll receive instructions on where to send the product.
Customers are responsible for return shipping costs unless the item was defective or incorrect.

Refunds
Refunds are issued to the original payment method once the returned item has been received and inspected.
Please allow 5–10 business days for the refund to appear on your account.
In some cases, a restocking fee may apply (if applicable, this will be disclosed during your return authorization).

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