
Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 8 - Jul 13
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 2017-2019 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:
- 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
4.2 ★★★★★
Based on 2034 reviews
Sort
Product Reviews
★★★★★ 5
Excellent Product, thanks!
Size: 10FT, Color: Black-20W
Excellent Product, thanks!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 3, 2026
★★★★★ 5
Great
Size: 6FT, Color: Black-20W
I used these in custom built nightstands, and customers loved them.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 4, 2026
★★★★★ 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.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 6, 2026
★★★★★ 5
Great value
Size: 50mm/2inch, Color: Black, Number of Items: 2
Great price. Worked perfectly.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 1, 2026
★★★★★ 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.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 10, 2026
recommand products
Esther Williams full length fashion film Dangerous When Wet 8b20-1624
11.49
Totally 90's Movie Trivia
25.00
MBRP 15-Up Can-Am OUtlander 450/500/570 US Market Only 5in Performance Series T304 Slip-on Exhaust
274.56
Disc Brake Rotor Centric Parts 320.34018H
83.86
Milano Round Wine Table (Light Pecan)
3360.00