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Ships within 48 hours · Estimated delivery Aug 22 - Aug 27
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For Your Every Summer RSVP, with Code: SUMMER15
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+ 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 add even more heat dissipation. This 2017+ 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 |
|---|---|---|---|
| 2021 | Chevrolet | Silverado 2500 HD | Custom |
| 2017-2021 | Chevrolet | Silverado 2500 HD | High Country |
| 2017-2021 | Chevrolet | Silverado 2500 HD | LT |
| 2017-2021 | Chevrolet | Silverado 2500 HD | LTZ |
| 2017-2021 | Chevrolet | Silverado 2500 HD | WT |
| 2017-2021 | Chevrolet | Silverado 3500 HD | High Country |
| 2017-2021 | Chevrolet | Silverado 3500 HD | LT |
| 2017-2021 | Chevrolet | Silverado 3500 HD | LTZ |
| 2017-2021 | Chevrolet | Silverado 3500 HD | WT |
| 2020-2021 | GMC | Sierra 2500 HD | AT4 |
| 2017-2021 | GMC | Sierra 2500 HD | Base |
| 2017-2021 | GMC | Sierra 2500 HD | Denali |
| 2017-2021 | GMC | Sierra 2500 HD | SLE |
| 2017-2021 | GMC | Sierra 2500 HD | SLT |
| 2020-2021 | GMC | Sierra 3500 HD | AT4 |
| 2017-2021 | GMC | Sierra 3500 HD | Base |
| 2017-2021 | GMC | Sierra 3500 HD | Denali |
| 2017-2021 | GMC | Sierra 3500 HD | SLE |
| 2017-2021 | GMC | Sierra 3500 HD | SLT |
Shipping Notes
- Free Standard Shipping on $100+ Orders 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
4.5 ★★★★★
Based on 10 reviews
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Product Reviews
★★★★★ 5
Cute addition!
Color: Black
As advertised. Good size for my sink area. Room for dish soap, hand soap pump and kitchen sponge. A place to hang my kitchen wash cloth too.
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Reviewed in the United States on January 22, 2026
★★★★★ 5
good buy
Color: Black
Nice looking, works well and well made.
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Reviewed in the United States on January 5, 2026
★★★★★ 4
Very sturdy and well designed organizer
Color: Black
Sturdy kitchen sink organizer. I measured and it truly is small. It holds large bottle soap, smaller bottle of cleaner, small round dish brush cleaner. The rack clips to the front and folds dish cloth. The tray slants toward sink for water to drain easily. I could have used a few inches longer. This makes a difference and I recommend for its sturdiness and useful design.
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Reviewed in the United States on May 23, 2026
★★★★★ 5
I like it
Color: Black
This is cute. It does the job. Has been about 4 months now and I see no signs of rust so at this point, I would reccomend.
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Reviewed in the United States on November 29, 2025
★★★★★ 5
Keeps my countertops neat & dry
Color: Black
The perfect accessory for our new sink & counter top. It keeps things & water off of our new counter top and a place to hang my dishrag!
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Reviewed in the United States on January 19, 2026