Pay in installments of $29.49 with
,
and
Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Aug 5 - Aug 10
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 full-flow thermal bypass valve upgrade for your 2017+ Chevrolet/GMC 6.6L Duramax. Our CNC-machined aluminum full-flow thermal bypass valve not only looks better than the stock unit, but it performs better too. This Mishimoto thermal bypass valve eliminates the internal thermostat, providing full fluid flow to the transmission cooler in all running conditions. This setup is ideal for owners in warm climates, those performing heavy towing, and trucks needing the best possible cooling efficiency for their transmission. 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 Full-Flow 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.
- 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
4.3 ★★★★★
Based on 11 reviews
Sort
Product Reviews
★★★★★ 5
Tennis balls save the day
Size: 16P, Color: colored
Good price and good quality of tennis balls
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 6, 2026
★★★★★ 5
Good balls
Size: 16P, Color: colored
Exactly what i needed
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 11, 2026
★★★★★ 1
Will not buy again
Size: 80P, Color: colored
We received the balls 5 days ago and so far our dog has destroyed a ball per day. At this rate, all the balls will be destroyed in 80 days. Not a good value for this product. We have other brand tennis balls that our dog has chewed on for months that have held up. We will not buy again.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 25, 2026
★★★★★ 5
Haven’t used them yet
Size: 80P, Color: colored
Haven’t used them yet but they appear to be good.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 17, 2026
★★★★★ 4
good for light chewers
Size: 16P, Color: yellow
Decent number of balls for the price! Unfortunately, my dog obliterated half of the tennis balls within an hour, but I'm sure part of that is because he likes to carry more than one ball at a time and chew on them a little before dropping for someone to throw. Otherwise, they are super bright, making them easy to see in the dark or dark places. They have some bounce to them, which makes playing fetch a little more exciting. My dog loves balls, so he has no complaints other than they don't squeak.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 27, 2026