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USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 14 - Jul 19
For Your Every Summer RSVP, with Code: SUMMER15
Description
Mishimoto Transmission Thermal Bypass Valve Kit 17-19 GM 6.6L Duramax L5PAre you wanting the best performance out of your Transmission? 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
Are you wanting the best performance out of your Transmission? 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. 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.
OPTIONAL THERMOSTAT DETAILS: This kit includes the removeable Thermostat 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.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
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
4.8 ★★★★★
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Product Reviews
★★★★★ 5
Bonito
Tal como la imagen
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Reviewed in the United States on February 5, 2026
★★★★★ 1
Bad quality overall
Terrible quality, has melted plastic, does not fit at all.
Please avoid this.
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Reviewed in the United States on July 31, 2025
★★★★★ 5
Clean
Look really clean I just need the side markers now
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Reviewed in the United States on April 9, 2024
★★★★★ 2
Won’t fit like oem
It doesn’t fit well and had to modify it to get it as close as possible
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Reviewed in the United States on February 1, 2026
★★★★★ 5
Look good :)
Style: Gloss Black Double Slats, Size: F30(2012-2018)
Good fitment, looks nice. The grill is easier to remove using a pick tool, no need to remove the bumper.
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Reviewed in the United States on October 20, 2025