Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit
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 Jul 9 - Jul 14

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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
  • 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]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 37194769079

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Verified Purchase
Jamie Betts
West Palm Beach, US
★★★★★ 1
Not Meant For Aggressive Chewers
Color: Brown Bird
Lasted 5 minutes. Definitely not for the aggressive chewers.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 12, 2026
T
Taylor
Dallas, US
★★★★★ 5
Strong toy
Color: Gray Bird
My dogs absolutely love this toy! I must get more. They are rly durable and I’d recommend this toy to others.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 10, 2026
R
Rob Kujovich
Whiting, US
★★★★★ 4
The toys body is very durable, but the squeakers were broken within minutes without tearing it apart
Color: Green Bird
This is a squeaky dog toy that was supposedly very durable. I have to say that the squeakers are not durable and were immediately destroyed by my husky. The actual body of the toy is very durable and they were not able to rip it apart. They were able to destroy the squeakers without damaging the actual exterior of this toy. The toy itself is pretty soft except where it’s made of rope. Since it didn’t have any stuffing come out I will say that it was durable enough for chewing. This would be suitable for large larger dogs and even smaller dogs. I do feel this is a good value for the money because they were not able to rip it apart. I just wish the squeakers were more durable inside because there’s no way to replace those.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 4, 2026
D
Darin Kelly
Lexington, US
★★★★★ 5
Our dogs new favorite toy
Color: Green Bird, Color: Green Bird
Our golden doodle loves this toy. He isn't a highly aggressive chewer necessarily, but he has been known to destroy toys by chewing on them and such. This one, so far, has lasted over a month or so. It has turned out to be his go to toy when he's wanting to play with one. The squeaker isn't that loud and it's not that easy to find. I like that legs are rope material and makes it good for tug of war, which Max loves to do. The material is pretty sturdy and it is a good weight. Sometimes when the toys are too heavy Max won't catch them in the air, this one he catches in the air just fine. It's very cute and I think it will hold up just fine to our Max's level of chewing. I felt the price was quite reasonable considering how much he likes it.
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Reviewed in the United States on May 2, 2026
L
Verified Purchase
Lapayswa Nimmons
Fort Morgan, US
★★★★★ 2
My dog destroyed this toy in 72 hours
Color: Blue Bird, Color: Blue Bird
Loved the toy but unfortunately this indestructible toy was destroyed by my Yorkie puppy in 3 days
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Reviewed in the United States on April 6, 2026

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