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The Mishimoto Full-Flow Transmission Thermal Bypass Valve Kit is engineered specifically for 2017-2019 Chevrolet Silverado and GMC Sierra 2500HD/3500HD trucks equipped with the 6.6L Duramax L5P diesel engine. This upgrade addresses common issues with the stock thermal bypass valve, which is prone to failure and can lead to transmission overheating. By replacing the factory unit with this CNC-machined billet-aluminum valve, you ensure a more reliable and efficient cooling system that maintains optimal transmission fluid temperatures under heavy towing or high-temperature conditions.
The design eliminates the internal thermostat, providing unrestricted fluid flow to the transmission cooler at all times, which is essential for maintaining transmission health during demanding driving situations. Strategically machined internal passages inside the valve improve flow capacity compared to stock components, while integrated cooling fins increase heat dissipation, helping to prevent overheating and extend transmission life.
Installation is straightforward, taking less than an hour, and the durable black anodized finish ensures long-lasting performance. This kit is an excellent choice for owners in warm climates, those performing frequent heavy-duty towing, or anyone seeking to optimize their vehicle’s transmission cooling efficiency. Built to last a lifetime, this Mishimoto product is backed by a lifetime warranty, guaranteeing quality and performance for years to come.
Features:
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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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
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Refunds
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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).
