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Regular Price: $146.56

Sale Price $124.95

  • Direct-fit for 2012-2018 Jeep Wrangler JK*
  • Installs in less than 1 hour
  • Durable CNC-machined billet aluminum design
  • Increased flow over stock bypass valve
  • Additional features below
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  • Direct-fit for 2012-2018 Jeep Wrangler JK*
  • Installs in less than 1 hour
  • Durable CNC-machined billet aluminum design
  • Increased flow over stock bypass valve
  • Includes 160°F thermostat to match stock valve opening temp
  • Customize the valve's opening temp with a range of Mishimoto thermostats
  • Fully serviceable thermostat for fast warm-up in cold climates and thermostat bypass for constant cooling in hot climates**
  • Machined cooling fins for added heat dissipation
  • Durable anodized finish
  • Mishimoto Lifetime Warranty


The transmission in your 2012-2018 Jeep Wrangler JK is the heart of its drivetrain. Whether you're hauling groceries or hitting the trail, it's vital to keep it performing at its best, and keeping the transmission fluid cool is crucial to that goal.

In an attempt to balance driveability and the health of your transmission, Jeep fitted a thermostatic bypass valve to the lines that feed the transmission cooler. This valve ensures fluid doesn't flow through the cooler before the transmission reaches operating temperature, preventing overcooling in cold environments. However, when the thermostat in this valve fails, it's almost a guarantee your transmission will overheat. Moreover, those who live in hot climates will likely never have to worry about overcooling, rendering the valve a useless flow restriction.

That's why Mishimoto has developed a performance thermostatic bypass valve for the 2012-2018 Jeep Wrangler JK. Our performance thermostatic bypass valve features a fully-serviceable and removable thermostat. For those who live in hot climates, the thermostat can be replaced with the included bypass to allow full flow to the transmission cooler at all times. Speaking of flow, the Mishimoto performance thermostatic bypass provides increased flow over the stock valve to ensure your transmission cooler operates at peak efficiency, even with the thermostat installed. The included thermostat opens at the stock temperature of 160°F (71°C), but the valve can be customized to suit your needs with any available Mishimoto thermostat.

The Mishimoto performance thermostatic bypass valve is a direct-fit* and is made from durable aircraft-grade aluminum that's anodized to withstand even the harshest environments. Like all of our Jeep products, our performance thermostatic bypass valve is backed by our Mishimoto Lifetime Warranty.


(1) CNC-Machined Billet Aluminum Thermal Bypass Valve
(1) Removable Thermostat
(1) Removable Thermostat Bypass w/ Installation Hardware
(1) Assembly Notecard
Mishimoto Lifetime Warranty


*This performance thermostatic bypass valve only fits vehicles with 5-speed automatic transmissions**Mishimoto does not recommend customers in cold climates install the thermostat bypass to avoid overcooling of the transmission fluid



Engine Codes LH
5.7 Hemi
6.1 Hemi
6.4 Hemi
Chassis Codes LX
Fits *Fits Vehicles With 5-Speed Automatic Transmission*

Chrysler 300 V6 (2.7L) 2007-2008
Chrysler 300 V6 (3.5L) 2005-2010
Chrysler 300 V6 (3.6L) 2011-2014
Chrysler 300 V8 (5.7L) 2005-2013
Chrysler 300 V8 (6.1L) 2007-2010
Chrysler 300 V8 (6.4L) 2012
Dodge Magnum V6 (2.7L) 2007-2008
Dodge Magnum V6 (3.5L) 2005-2008
Dodge Magnum V8 (5.7L) 2005-2008
Dodge Magnum V8 (6.1L) 2006-2008
Dodge Charger V6 (2.7L) 2007-2008
Dodge Charger V6 (3.5L) 2006-2010
Dodge Charger V6 (3.6L) 2011-2019
Dodge Charger V8 (5.7L) 2006-2013
Dodge Charger V8 (6.1L) 2006-2010
Dodge Charger V8 (6.4L) 2012-2013
Dodge Nitro V6 (3.7L) 2007-2008
Dodge Nitro V6 (4.0L) 2007-2011
Dodge Ram 1500 V8 (4.7L) 2012-2013
Dodge Ram 1500 V8 (5.7L) 2012-2020
Dodge Ram 2500 V8 (5.7L) 2012-2013
Jeep Grand Cherokee V6 (3.0L) 2007-2009
Jeep Grand Cherokee V6 (3.6L) 2011-2013
Jeep Grand Cherokee V6 (3.7L) 2007-2010
Jeep Grand Cherokee V8 (4.7L) 2007
Jeep Grand Cherokee V8 (5.7L) 2007
Jeep Grand Cherokee V8 (6.1L) 2007-2010
Jeep Grand Cherokee V8 (6.4L) 2012-2013
Jeep Liberty V6 (3.7L) 2011-2012
Jeep Commander V6 (3.7L) 2008-2010
Jeep Wrangler V6 (3.6L) 2012-2018


OEM Activation Temp C 71°C
OEM Activation Temp F 160°F
Mishimoto Activation Temp (Fahrenheit)160°F
Mishimoto Activation Temp (Celsius)71°C

Coronary Graft – Thermal Bypass R&D – Concept and Design

December 07, 2021

The transmission in your JK Wrangler is practically the essence of what makes it a Jeep. The sturdy gear sets housed inside, transferring power from the engine, give the Wrangler its go anywhere, do anything attitude. Jeeps pride themselves on being ready for any situation, from the dusty trails to mall parking lots, but are … Continue reading Coronary Graft – Thermal Bypass R&D – Concept and Design →

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Coronary Graft – Thermal Bypass R&D – Concept and Design

Mishimoto Automotive (“Mishimoto”) warrants its products under this lifetime limited warranty policy (“Warranty Policy”). This Warranty Policy applies solely to: (i) Mishimoto Products purchased directly from Mishimoto or Mishimoto authorized dealers (each a “Mishimoto Product” and collectively, the “Mishimoto Products”) and (ii) the original purchaser of such Mishimoto Product (“Purchaser”). This Warranty Policy is non-transferable and all claims under this Warranty Policy must be accompanied by the original sales receipt. The terms and conditions of this Warranty Policy are subject to change by Mishimoto at any time without notice.

For our complete warranty policy, please click here.

Mishimoto Lifetime Warranty on ALL Products
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