SKU: 30094805112

Mishimoto 2017+ GMC 6.6L Duramax L5P Transmission Thermal Bypass Valve Kit

Sale price$133.19 Regular price$147.99
Save 10%

Pay in installments of $37.00 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 12 - Aug 17

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 2017-2019 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:
  1. 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
SKU: 30094805112

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.6 ★★★★★
Based on 12 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
C
Verified Purchase
Curtis Brooks
West Palm Beach, US
★★★★★ 5
Great Mechanical Self-winder
Color: Black
Wow! So far I have only adjusted the time three times over the last few months. So far It keeps great time and looks good. Well worth the money after having blown a few dollars on less expensive mechanical watches that fail after only a few months of use. This thing is very good!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 11, 2024
M
Verified Purchase
Mark D. Reiners
Carnegie, US
★★★★★ 4
Beautiful
Color: All black
Having never previously owned a self-winding watch, and because the wristband did require some link-removal adjustment, I did hold off on wearing it for a few days until I could schedule an appointment with my jeweler to have the day/date setting and band-adjustment done. But a major part of my reason for doing so was my strong impression upon receipt of the watch that this was a very good choice. It is a very beautiful watch to look at, though compact and not overly bulky like many chronograph-style watches, its' heft conveyed a sense of a very solid, well designed and constructed watch. Since having the setting and adjustments done, I have been extremely pleased with how accurately it keeps time. In short, I LOVE this watch. I will also note this. Though my jeweler retails various high-end, and much more expensive watches, he was clearly impressed with the look and feel of this watch, and even made explicit comment about what a beautiful watch he felt it was. That said, I do have a quibble. The writing of the accompanying instruction booklet was riddled with English grammatical errors which were quite frustrating, and contributed to my reason for opting to have my jeweler complete the settings and adjustment. Also, when I contacted OLEV online to solicit guidance on how to expedite registering the purchase for warranty purposes, I received an email auto response saying that any Amazon purchase would require customer service and other guidance through the seller. Since my assumption upon Amazon purchase was that I WAS purchasing from OLEV as the seller, this remains a source of confusion which I yet need to resolve.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 3, 2024
P
Verified Purchase
PN
Lake Worth, US
★★★★★ 1
Doesn’t keep accurate time
Color: All black
I bought this for my husband because it said that it self winds but my husband noticed that it didn’t work within the first few days so I thought maybe it was defective so I purchased another one in exchange for the first one but the second one had the same issue. Don’t waste your money on this, it doesn’t work.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 14, 2025
F
Verified Purchase
Francis Orina
Alexandria, US
★★★★★ 3
Substandard,always donated of time when it works.it had be set on a daily
Color: Black
Stops frequently,sometimes have to give a few days for the clock to start functioning sgain
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 23, 2026
W
Verified Purchase
Whit777
Alexandria, US
★★★★★ 5
Awesome watch highly recommend
Color: All black, Color: All black
My husband bought me this brand of watch for my birthday and it’s so awesome. It looks blingy but not in a bad way. Kinda looks like a Rolex. No battery.I bought him a one and he loves it .
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 22, 2025

recommand products