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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Ships within 48 hours · Estimated delivery Jul 19 - Jul 24

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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
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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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4.5 ★★★★★
Based on 14 reviews
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Lesley
Whiting, US
★★★★★ 5
Withstands big dog
Color: Green Cactus
As a dog mom to two active pups, I’ve gone through a LOT of chew toys over the years and honestly, many of them just didn’t hold up. Some cracked, broke apart quickly, or became rough after only a short time of chewing. That’s why I was genuinely impressed with the MewaJump chew toy. Both of my dogs immediately loved it, and what stood out most to me was how durable it’s been compared to other toys we’ve tried. It’s held up really well with aggressive chewing while still seeming safe and comfortable for them to use. I also love that it keeps them entertained and engaged longer without constantly worrying about pieces breaking off. Definitely one of the better dog toys we’ve added to our home lately and Molly and Piper would agree.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 15, 2026
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Verified Purchase
THAILEI L SMITH
Pawtucket, US
★★★★★ 5
Not recommended for strong chewers.
Color: Green Cactus
There was nothing wrong with this. But my dog is an absolute destroyer. She makes it her personal mission to annihilate any toy I buy. This did not last 30 minutes. Very cute and good for normal dogs that like to actually have toys to play with. Do not recommend for strong jaw destroyers.
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Reviewed in the United States on June 8, 2026
D
Verified Purchase
DianaZ
Dallas, US
★★★★★ 5
Fun and indestructible!
Color: Green Cactus
The dogs love this toy. And so far it’s been indestructible with constant playing and chewing
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Reviewed in the United States on June 5, 2026
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Verified Purchase
Lauren
Los Angeles, US
★★★★★ 4
Durable for light to medium chewers - not heavy
Color: Green Cactus
obviously cute. not super durable - lasted a good minute but disintegrates fairly quickly and eventually nothing was left - having to high monitor with a big chewer. (10 mo Great Dane)
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Reviewed in the United States on April 4, 2026
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Verified Purchase
Amazon Customer
Phoenix, US
★★★★★ 5
Unbelievable toy for aggressive chewers
Color: Green Cactus
Great toy for aggressive chewers! I'm not one to hand out 5 star reviews but this one I 100% believe in. I bought the first one in 2023 and just replaced it because it broke. Now this is not a played with every once in a while, this was played with daily as it is his favorite toy. Very few toys last long but this one has went beyond my expectations. Could not be happier.
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Reviewed in the United States on May 28, 2026

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