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 8 - Jul 13

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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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Samuel Ocampo
New York, US
★★★★★ 5
Excellent Product, thanks!
Size: 10FT, Color: Black-20W
Excellent Product, thanks!
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Reviewed in the United States on May 3, 2026
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Thomas Murray
Houston, US
★★★★★ 5
Great
Size: 6FT, Color: Black-20W
I used these in custom built nightstands, and customers loved them.
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Reviewed in the United States on May 4, 2026
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Mike S
Carnegie, US
★★★★★ 5
Does what I needed it to do
Size: 50mm/2inch, Color: Black, Number of Items: 4
Worked perfectly for routing all my wires for my desk. The included tie straps were an added bonus. Now everything is nice, tidy and secured to the back side of my rolling desk.
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Reviewed in the United States on May 6, 2026
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Amazon Customer
Los Angeles, US
★★★★★ 5
Great value
Size: 50mm/2inch, Color: Black, Number of Items: 2
Great price. Worked perfectly.
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Reviewed in the United States on May 1, 2026
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Barry Robinson
Lowell, US
★★★★★ 5
Great to clean up the cable clutter
Size: 50mm/2inch, Color: Black, Number of Items: 4
I finally got around to cleaning up the cable disaster on my home office desk and these grommets were exactly what I needed. They fit perfectly into the 2-inch holes I drilled, and the plastic feels surprisingly sturdy, not like that cheap, brittle stuff that snaps the moment you try to pop the cover back on. The little brush-like opening is a nice touch because it keeps the cords from sliding back down when they aren't plugged in, and the black finish looks really clean against my wood tabletop. For a 4-pack, the price was a total steal, and it honestly makes the whole setup look way more professional than just having raw holes in the desk. If humans are looking for a quick and cheap way to hide cord clutter, these are a solid bet.
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Reviewed in the United States on February 10, 2026

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