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Automatic Transmission Oil Cooler (Mishimoto) for 2017-2021 Chevrolet & GMC NEW

$ 99 .95

Product Notes

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.
Brand: Mishimoto
Condition: New
LIFE
TIME
Lifetime Warranty Included
This part is backed by our industry-leading lifetime warranty. Shop with total confidence.
100%money-back 120-dayreturns OE-gradequality
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Specifications & Info


Attribute Value
Install Difficulty 1
SellingPoint01 Direct Fit For 2017+ Chevrolet/gmc 6.6l Duramax L5p
SellingPoint02 Installs In Less Than 1 Hour
SellingPoint03 Eliminates Failure-prone Bypass Valve
SellingPoint04 Durable Cnc-machined Billet-aluminum Construction
SellingPoint05 Full-flow Bypass Allows The Transmission Cooler To Operate At Maximum Efficiency
SellingPoint06 Helps Extend Transmission Life And Prevent Overheating
SellingPoint07 Fits With Stock Transmission Cooler Piping, Requiring No Modification For Installation
SellingPoint08 Integrated Heat-sink Fins Provide Unique Styling And Added Heat Dissipation
SellingPoint09 Durable Anodized Finish
SellingPoint10 Mishimoto Lifetime Warranty
SellingPoint11 N/a
SellingPoint12 N/a
SellingPoint13 N/a
SellingPoint14 N/a
SellingPoint15 N/a
TechSpec Applications Gmc Sierra 2500hd V8 (6.6l Diesel) 2017+--gmc Sierra 3500hd V8 (6.6l Diesel) 2017+--chevrolet Silverado 2500hd V8 (6.6l Diesel) 2017+--chevrolet Silverado 3500hd V8 (6.6l Diesel) 2017+
TechSpec Chassis Codes 2500--3500
TechSpec Engine Codes L5p--6.6l Duramax
TechSpec Includes (1) Cnc-machined Billet Aluminum Thermal Bypass Valve--(2) 7/8-inch X 14 Quick-disconnect Transmission Line Fittings--(1) Transmission Line Mounting Plate--(1) Transmission Line Mounting Plate Bolt--mishimoto Lifetime Warranty
TechSpec Mishimoto Activation Temperature (F) N/a
TechSpec Note Mishimoto Does Not Recommend Customers In Cold Climates Install The Thermostat Bypass To Avoid Overcooling Of The Transmission Fluid----this Performance Thermostatic Bypass Valve Only Fits Vehicles Equipped With The Allison Automatic Transmission----
TechSpec OEM Activation Temperature (F) 185

Vehicle Fitment Guide

This part fits the following vehicles:

Chevrolet 2 models (tapclick to expand)(tapclick to hide)
Silverado 2500 HD 2017-2021 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL
Body Style Years Engine Attributes
Custom Crew Cab Pickup 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Custom Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Custom Extended Cab Pickup 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Custom Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
High Country Crew Cab Pickup 2020 - 2021 V8 6.6L 4WD Automatic
High Country Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
High Country Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
High Country Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo 4WD Automatic
High Country Crew Cab Pickup 2017 - 2019 V8 6.6L DIESEL Turbo RWD Automatic
LT Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Crew Cab Pickup 2018 - 2019 V8 6.0L CNG RWD/4WD Automatic
LT Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
LT Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LT Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LT Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Extended Cab Pickup 2018 - 2019 V8 6.0L CNG RWD/4WD Automatic
LT Extended Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
LT Extended Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LT Extended Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LT Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Standard Cab Pickup 2018 V8 6.0L CNG RWD/4WD Automatic
LT Standard Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
LT Standard Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
LT Standard Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LTZ Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LTZ Crew Cab Pickup 2018 - 2019 V8 6.0L CNG RWD/4WD Automatic
LTZ Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
LTZ Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LTZ Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LTZ Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LTZ Extended Cab Pickup 2018 V8 6.0L CNG RWD/4WD Automatic
LTZ Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
LTZ Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
LTZ Extended Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Crew Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Crew Cab Pickup 2018 - 2019 V8 6.0L CNG RWD/4WD Automatic
WT Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
WT Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
WT Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Extended Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Extended Cab Pickup 2018 - 2019 V8 6.0L CNG RWD/4WD Automatic
WT Extended Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
WT Extended Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
WT Extended Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Standard Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Standard Cab Pickup 2018 - 2019 V8 6.0L CNG RWD/4WD Automatic
WT Standard Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
WT Standard Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
WT Standard Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Silverado 3500 HD 2017-2021 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL
Body Style Years Engine Attributes
Base Cab & Chassis 2020 - 2021 V8 6.6L RWD Automatic
High Country Crew Cab Pickup 2020 - 2021 V8 6.6L 4WD Automatic
High Country Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
High Country Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
High Country Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo 4WD Automatic
High Country Crew Cab Pickup 2017 - 2019 V8 6.6L DIESEL Turbo RWD Automatic
LT Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
LT Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
LT Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
LT Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
LT Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LT Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LT Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LT Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LT Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
LT Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
LT Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LT Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LT Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
LT Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
LT Extended Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LT Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LT Standard Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
LT Standard Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
LT Standard Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LTZ Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
LTZ Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
LTZ Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
LTZ Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
LTZ Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
LTZ Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
LTZ Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
LTZ Extended Cab Pickup 2017 - 2018 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Cab & Chassis 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Cab & Chassis 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
WT Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
WT Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
WT Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
WT Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
WT Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
WT Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Crew Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
WT Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
WT Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
WT Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Extended Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
WT Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
WT Extended Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
WT Standard Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
WT Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
WT Standard Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
WT Standard Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
WT Standard Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
GMC 2 models (tapclick to expand)(tapclick to hide)
Sierra 2500 HD 2017-2021 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL
Body Style Years Engine Attributes
AT4 Crew Cab Pickup 2020 - 2021 V8 6.6L 4WD Automatic
AT4 Crew Cab Pickup 2020 - 2021 V8 6.6L DIESEL Turbo 4WD Automatic
Base Crew Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
Base Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
Base Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Base Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Base Extended Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Extended Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
Base Extended Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
Base Extended Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Base Extended Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Base Standard Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Standard Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
Base Standard Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
Base Standard Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Base Standard Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Denali Crew Cab Pickup 2020 - 2021 V8 6.6L 4WD Automatic
Denali Crew Cab Pickup 2019 V8 6.0L RWD/4WD Automatic
Denali Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Denali Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo 4WD Automatic
Denali Crew Cab Pickup 2017 - 2019 V8 6.6L DIESEL Turbo RWD Automatic
SLE Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
SLE Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
SLE Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLE Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLE Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Extended Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
SLE Extended Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
SLE Extended Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLE Extended Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLE Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Standard Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
SLE Standard Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
SLE Standard Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLT Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLT Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
SLT Crew Cab Pickup 2017, 2019 V8 6.0L RWD/4WD Automatic
SLT Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLT Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLT Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLT Extended Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
SLT Extended Cab Pickup 2017, 2019 V8 6.0L RWD/4WD Automatic
SLT Extended Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLT Extended Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Sierra 3500 HD 2017-2021 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL
Body Style Years Engine Attributes
AT4 Crew Cab Pickup 2020 - 2021 V8 6.6L 4WD Automatic
AT4 Crew Cab Pickup 2020 - 2021 V8 6.6L DIESEL Turbo 4WD Automatic
Base Cab & Chassis 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Cab & Chassis 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
Base Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
Base Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
Base Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
Base Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Base Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Base Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Base Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Base Crew Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
Base Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
Base Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Base Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Base Extended Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
Base Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
Base Extended Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Base Standard Cab Pickup 2021 V8 6.6L FLEX RWD/4WD Automatic
Base Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
Base Standard Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
Base Standard Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
Base Standard Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Denali Cab & Chassis 2019 V8 6.0L RWD/4WD Automatic
Denali Cab & Chassis 2019 V8 6.0L FLEX RWD/4WD Automatic
Denali Cab & Chassis 2019 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Denali Crew Cab Pickup 2020 - 2021 V8 6.6L 4WD Automatic
Denali Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
Denali Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
Denali Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo 4WD Automatic
Denali Crew Cab Pickup 2017 - 2019 V8 6.6L DIESEL Turbo RWD Automatic
SLE Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Cab & Chassis 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
SLE Cab & Chassis 2019 V8 6.0L CNG RWD/4WD Automatic
SLE Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
SLE Cab & Chassis 2017 - 2019 V8 6.0L RWD/4WD Automatic
SLE Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLE Cab & Chassis 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLE Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLE Cab & Chassis 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLE Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
SLE Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
SLE Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLE Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLE Extended Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
SLE Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
SLE Extended Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLE Standard Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLE Standard Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
SLE Standard Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
SLE Standard Cab Pickup 2017 - 2018, 2020 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLT Crew Cab Pickup 2020 - 2021 V8 6.6L RWD/4WD Automatic
SLT Crew Cab Pickup 2019 V8 6.0L CNG RWD/4WD Automatic
SLT Crew Cab Pickup 2017 - 2019 V8 6.0L RWD/4WD Automatic
SLT Crew Cab Pickup 2017 - 2019 V8 6.0L FLEX RWD/4WD Automatic
SLT Crew Cab Pickup 2017 - 2021 V8 6.6L DIESEL Turbo RWD/4WD Automatic
SLT Extended Cab Pickup 2017 - 2018 V8 6.0L RWD/4WD Automatic
SLT Extended Cab Pickup 2017 - 2018 V8 6.0L FLEX RWD/4WD Automatic
SLT Extended Cab Pickup 2017 - 2018 V8 6.6L DIESEL Turbo RWD/4WD Automatic
Verify before ordering — please confirm your vehicle's year, make, model and sub-model specifications before placing your order. If anything is unclear, our customer service team is available to help.

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Shipping Information

We offer fast, reliable shipping on all orders:

  • Ships to all countries via US Postal Service Priority Mail.
  • Most orders ship within 1 business day.
  • Delivery time: 1-4 business days after shipment.
  • International shipping available, including APO/FPO addresses.
  • Tracking information provided for all shipments.
  • Additional handling fees may apply for oversized/overweight packages.

Return Policy

We want you to be 100% satisfied with your purchase. That's why we offer:

  • 120-Day Returns - Return any part within 120 days from date of receipt.
  • Must obtain RMA (Return Merchandise Authorization) number before returning.
  • Parts must be in original condition, uninstalled, unaltered, and in original packaging.
  • Important: Electrical parts are not returnable if unsealed.
  • Please inspect parts upon arrival and notify us within 5 days of receiving incorrect or damaged parts.
  • Refunds processed after warehouse receives return and credited to original payment method.

Warranty

This part comes with a limited lifetime warranty. Warranty begins on the original purchase date.

Warranty does NOT cover:

  • Shipping costs or labor expenses.
  • Installation errors.
  • Parts used for racing.
  • Commercial vehicle parts.
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.

Fits Years: 2017 2018 2019 2020 2021

Fits Models: Sierra 2500 HD, Sierra 3500 HD, Silverado 2500 HD, Silverado 3500 HD

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