SKU: 3942758100

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

Sale price$133.16 Regular price$147.95
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USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 20 - Jul 25

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Description

Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve KitThe Allison transmission is the backbone of your L5P Duramax. It's responsible for transmitting large quantities of torque from your V8 diesel powerplant. This torque generates a lot of heat, and if that heat isn't dissipated, it can destroy your transmission. The transmission cooler does a good job of keeping trans fluid temperatures in check, but only if the fluid can reach it. The stock cooling system of the Allison 1000 transmission utilizes an in

The Allison transmission is the backbone of your L5P Duramax. It's responsible for transmitting large quantities of torque from your V8 diesel powerplant. This torque generates a lot of heat, and if that heat isn't dissipated, it can destroy your transmission. The transmission cooler does a good job of keeping trans fluid temperatures in check, but only if the fluid can reach it. The stock cooling system of the Allison 1000 transmission utilizes an in-line thermal bypass valve that controls fluid flow to the transmission cooler. The purpose of this valve is to prevent transmission fluid from flowing to the cooler until it reaches operating temperature. The thermostat inside this valve is prone to failure, however, and when that happens, the fluid never flows to the cooler, and the transmission can overheat. That's why Mishimoto has developed a thermal bypass valve upgrade for your 2017+ Chevrolet/GMC 6.6L Duramax. Our CNC-machined aluminum thermal bypass valve not only looks better than the stock unit, but it performs better too. This Mishimoto thermal bypass valve kit includes a fully serviceable thermostat for fast warm-up in cold climates. This kit also includes a thermostat bypass that can be installed to provide constant cooling in warm climates or for use in extreme driving/towing conditions. The Mishimoto thermal bypass valve features strategically machined internal passages, providing improved flow over the stock valve for more effective cooling. In addition, cooling fins machined into the valve body add even more heat dissipation. This 2017+ Chevrolet/GMC 6.6L Duramax L5P Thermal Bypass Valve Kit is built to last a lifetime with a durable black anodized finish and our Mishimoto Lifetime Warranty.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
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SKU: 3942758100

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4.1 ★★★★★
Based on 24 reviews
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G
Verified Purchase
Good product, Not easy to install
Carnegie, US
★★★★★ 5
Not fit for 2023 Highlander
Size: 9.7" x 9.3" x 1.8", Size: 9.7" x 9.3" x 1.8"
Product quality is good, that's why I give 5 stars. However it was not fit for my 2023 Toyota Highlander,, so returned.
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Reviewed in the United States on May 3, 2026
J
Verified Purchase
JPM
Lexington, US
★★★★★ 5
Air flow direction
Size: 9.7" x 9.3" x 1.8"
Good product. Fits fine. This is not a Toyota part so Air Flow Arrows on filter should face down in a 2015 Toyota Rav4.
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Reviewed in the United States on March 27, 2026
B
Verified Purchase
brian
Omaha, US
★★★★★ 5
Better upgrade for older BMW
Material Type: Plastic
Perfect fit
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Reviewed in the United States on March 20, 2026
A
Verified Purchase
Amanda
Pawtucket, US
★★★★★ 5
Amazing
Material Type: Plastic
I purchased the Front Center Console Cup Holder as a replacement and it worked perfectly. The fit was very good and it matched the interior of the car nicely. It feels sturdy and holds cups securely without them moving around while driving. Installation was simple and took just a few minutes. It’s a great solution if your original cup holder is broken, worn out,
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Reviewed in the United States on March 7, 2026
C
Verified Purchase
Cheto
Louisville, US
★★★★★ 5
Works great
Material Type: Plastic
Good quality overall
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Reviewed in the United States on March 7, 2026

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