SKU: 37194769079

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

Sale price$148.49 Regular price$164.99
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Ships within 48 hours · Estimated delivery Aug 23 - Aug 28

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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 2017-2019 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 adds even more heat dissipation. This 2017-2019 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.

This Part Fits:

Year Make Model Submodel
2017-2019 Chevrolet Silverado 2500 HD High Country
2017-2019 Chevrolet Silverado 2500 HD LT
2017-2019 Chevrolet Silverado 2500 HD LTZ
2017-2019 Chevrolet Silverado 2500 HD WT
2017-2019 Chevrolet Silverado 3500 HD High Country
2017-2019 Chevrolet Silverado 3500 HD LT
2017-2019 Chevrolet Silverado 3500 HD LTZ
2017-2019 Chevrolet Silverado 3500 HD WT
2017-2019 GMC Sierra 2500 HD Base
2017-2019 GMC Sierra 2500 HD Denali
2017-2019 GMC Sierra 2500 HD SLE
2017-2019 GMC Sierra 2500 HD SLT
2017-2019 GMC Sierra 3500 HD Base
2017-2019 GMC Sierra 3500 HD Denali
2017-2019 GMC Sierra 3500 HD SLE
2017-2019 GMC Sierra 3500 HD SLT
Shipping Notes
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Exchange/Return Notes
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SKU: 37194769079

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Brooklyn
Natrona Heights, US
★★★★★ 5
Dogs favorite toy
Color: Orange & Blue Roller, Size: 7.5 inches (1 Pack), Color: Orange & Blue Roller, Size: 7.5 inches (1 Pack)
I buy 4 of these every month for my dog. He won’t go anywhere without this ball. He sleeps with it, swims with it, goes to the vet and carries it around in his mouth to show off. It’s borderline a problem. My dog is a large breed and plays hard so I do purchase often because the strings unravel and the ball itself is foam so breaks down into little pieces after a few days of playing. I love that it is fragile on his teeth and jaw. We can play catch indoors because it is soft.
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Reviewed in the United States on March 24, 2026
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NATTY
Grantham, US
★★★★★ 5
Love It!
Color: Orange & Blue Fetch Ball, Size: 4.75 inches (1 Pack)
Perfect for your dog who loves to play ball indoors. It doesn’t bounce & it’s very soft. It lasted a long time for a German Shepherd who loveeess to ball all day.
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Reviewed in the United States on June 10, 2026
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susan schwartz
New York, US
★★★★★ 5
Just what we needed
Color: Orange & Blue Squirrel, Size: 4.7 inches (1 Pack)
This toy has been great for my dog who eats all her toys! We were having such an issue with all of her toys being so hard that we didn’t want to throw them around our house. This was the perfect solution. She hadn’t eaten through it and it’s nice and soft for fetch without destroying your house!
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Reviewed in the United States on June 3, 2026
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Megan
Bozeman, US
★★★★★ 4
My lab loves t
Color: Orange & Blue Fumbler, Size: 3 x 8.5 x 9 inches (1 Pack)
This toy is my labs favorite toy. She’s obsessed and we were happy to find a toy she loves that can stay inside with us. The problem is how easily she tears it apart. We have to buy her a new one every month because when she bites into it it breaks down the foam inside, and from there she shreds the roping it’s covered in. We try to stop her, but with how often we play with it it’s inevitable. We have resigned ourselves to buying a new one once a month.
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Reviewed in the United States on April 7, 2026
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Heather E.
Phoenix, US
★★★★★ 5
Worth the purchase
Color: Orange & Blue Fumbler, Size: 3 x 8.5 x 9 inches (1 Pack)
Perfect for indoor use. My aggressive chewer loves this and has not destroyed it yet after 6 months. I recommend for indoor use as it causes NO damage or noise.
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Reviewed in the United States on May 24, 2026

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