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Ships within 48 hours · Estimated delivery Aug 3 - Aug 8
Promo Codes Available:
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.
- Except Preorder products are shipped in 48 hours.
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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
4.2 ★★★★★
Based on 11 reviews
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Product Reviews
★★★★★ 5
Great feel, good shirt
Size: Medium, Color: Black
I bought this to replace my excite Express 1MX button up black shirt for work uniform which kept fading with the seams turning a dull gray. The PJ shirt is wrinkle free after first wash, stays black, and is a bit more stretchy. Also it’s way more affordable at $26 vs Express 1MX at $60 ish.
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Reviewed in the United States on February 18, 2026
★★★★★ 5
PJ Paul Jones Dress Shirt
Size: X-Large, Color: Airy Blue
Nice Fit . Spring Fashions
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Reviewed in the United States on May 15, 2026
★★★★★ 5
Very nice shirts but unusually long sleeves
Size: Large, Color: Light Green
PJ PAUL JONES Mens Dress Shirts Wrinkle Free Stretch Button Down Shirt. I bought white, coffee, grey, autumn green and apricot. Colors are true to the ads. I'm 6' , 170 lbs. I bought these in Large. They fit very well in shoulders, chest, and my big belly. As many reviews have stated, the sleeves are unusually long - coming down past my palms to my fingers. I would give them a 4 rating for that but I bought them with the intention of making them short sleeve. The white shirt is just too nice to change so I'll reserve that for weddings and funerals. The apricot is very nice but I just wouldn't wear that color as a casual shirt but it does go with my brown blaser so I'll keep it for rare occasions. I washed them in warm and put them thru warm dryer and didn't notice any shrinkage which I wouldn't
expect with polyester. Very good shirts at very good price.
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Reviewed in the United States on March 30, 2026
★★★★★ 5
A Solid Buy
Size: XX-Large, Color: Black
Purchased this shirt to wear to a concert. I love the material because it's stretchy and flexible unlike the traditional cotton. It's mainly wrinkle free but I ran a warm iron to get out the creases from being folded. I wore this with gray pants and it made my outfit feel put together. The sleeves are very easy to roll up and won't come undone. A very nice shirt to add to your clothing collection.
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Reviewed in the United States on April 10, 2026
★★★★★ 4
Good looking shirt that runs a bit big in sizing.
Size: X-Large, Color: Green Gray
Nice looking shirt for dress up or casual wearing. Feels like silk, pretty wrinkle free. Lots of colors to chose from at a good price. Runs a bit big in size. I found the sleeves very long for me. But I like the casual look, feel and coolness in the heat of summer for a long sleeve shirt.
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Reviewed in the United States on August 9, 2025