SKU: 48526865078

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

Sale price$89.95 Regular price$99.95
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Ships within 48 hours · Estimated delivery Aug 2 - Aug 7

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

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
  • Free Standard Shipping on $100+ Orders to the USA.
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  • 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: 48526865078

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4.3 ★★★★★
Based on 29 reviews
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Darlene E.
Alexandria, US
★★★★★ 5
Love this and very durable!!
Color: Blue Spider
This spider is HUGE! It's sooooooooo nice! My 3 boys love it! They love chewing on all the legs and it's so big that they can all lay around it and each chew on a leg at the same time! They also play tug of war with it at times! It's stuffed with a cushiony material. It does not bounce. It's lightweight. Has no smell. It's so much fun for my boys! Love it! It has great durability as my one boy who literally destroys all his toys has not broken it and they've had it for 3 months so far! This alone speaks volumes! Highly recommend!
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Reviewed in the United States on March 26, 2026
M
Verified Purchase
Mary
Port Orchard, US
★★★★★ 5
Dog toy
Color: Blue Octopus
Great dog toy very durable great 2 dogs to play tug of war
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Reviewed in the United States on June 9, 2026
A
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anchoredsoul36
Houston, US
★★★★★ 4
Aggressive chewer (terrier) approved!
Color: Blue Octopus
I would give five stars except for one small area. The back seam was too easy to access to get the squeaker out (literally under half an hour of him playing). ***BUT*** the legs are SO strong and can be used for tug of war and they are crinkly and he loves it. Highly recommend!
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Reviewed in the United States on April 13, 2026
H
Verified Purchase
Hayden
Draper, US
★★★★★ 3
Not bad, wish it was more durable
Color: Blue Octopus
My Australian Shepard loved this toy! However, it is NOT VERY DURABLE as advertised. He ripped off a leg within 20 minutes of getting the toy.
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Reviewed in the United States on June 6, 2026
S
Verified Purchase
Seymourstreet
Port Orchard, US
★★★★★ 5
GREAT FOR MY LITTLE ADOPTED DOG!
Color: 6 pack
These little soft dog toys are wonderful for small to medium sized dogs. I recently rescued a dog who had never seen a toy, nor did she know how to play with them and these are perfect. She is a 13 pound half Chihuahua/terrier mix, and she loves to play with these little toys. They’re cute to me and she likes them so that makes me happy.
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Reviewed in the United States on April 5, 2026

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