SKU: 25597115635

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

Sale price$89.95 Regular price$99.95
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  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 16 - Aug 21

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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 full-flow thermal bypass valve upgrade for your 2017+ Chevrolet/GMC 6.6L Duramax. Our CNC-machined aluminum full-flow thermal bypass valve not only looks better than the stock unit, but it performs better too. This Mishimoto thermal bypass valve eliminates the internal thermostat, providing full fluid flow to the transmission cooler in all running conditions. This setup is ideal for owners in warm climates, those performing heavy towing, and trucks needing the best possible cooling efficiency for their transmission. 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 Full-Flow 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
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SKU: 25597115635

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4.4 ★★★★★
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Dianna H
San Leandro, US
★★★★★ 5
Not Scented, but Dog Approved
Size: 2-pack, Style: Duo
They don't smell like peanut butter or bacon. But our dogs still love them.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 31, 2025
W
Verified Purchase
waragon
Boise, US
★★★★★ 4
If they squeaked, they would be the perfect ball!
Size: 2-pack, Style: Duo
I bought our 15 month old Coton several Chuck-It toys on an Amazon deal. He is incredibly playful, mischievous, and ball/toy obsessed, especially for anything that makes noise. He can also be very destructive so I love how durable most of their products are - they’re among our longest lasting toys and worth every penny. We have yet to take them to the dog park, but they’re a perfect size for sharing in plat time. And they are keeping him busy at home - that’s a good thing. The scent is subtle but strong enough for him I guess because he loves gnawing on them. If they had squeakers, they would be absolutely perfect. Hopefully Chuck-It will see an opportunity for that down the road!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 28, 2026
R
Verified Purchase
Reepeat
Dallas, US
★★★★★ 5
Most durable fetch balls I know of.
Size: 2-pack, Style: Duo
These balls are the biggest balls of them all. Well, not the biggest, but the best. Every other ball she would chew up in short order and I'd be throwing her a floppy piece of rubber. She just wants to fetch, but if it's not bouncing, she can't catch it on the bounce. Got these balls in July and no damage to them. I just ordered another pair, but only because the other two somehow got stuck up in trees. We have some very old and very large oak trees so not so easy to retrieve. Hope they somehow drop someday. But in the meantime, Lassie will be happy with her new ones. Very highly recommended!
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Reviewed in the United States on October 28, 2025
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Blonde Aggie
Los Angeles, US
★★★★★ 5
Works great for scent work! Bounce is great for air retrieve!
Size: 2-pack, Style: Duo, Size: 2-pack, Style: Duo
My dog doesn’t know he loves them yet but I do! They are a little softer so when we do air retrieve, I don’t have to worry as much about his teeth! I’m hoping he will learn to find them by smell vs sight. We often play in the evenings and he tends to loose his ball. Love chuck it! Right now, we have about 10 chuck it balls! The tennis balls don’t work for air retrieve! Chuckit does!!! Love the thrower too! Saves my arm!!!!
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Reviewed in the United States on August 6, 2025
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None of your business
Massapequa, US
★★★★★ 3
I guess the smell is offputting
Size: 2-pack, Style: Duo
My dog loves chocolate stuff. But for some reason, wasn’t a huge fan of these balls. She played with them a little bit, but they’re not her favorite.
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Reviewed in the United States on December 30, 2025

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