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

Posted: December 30, 2020

Categories: Jeep Wrangler JK Thermal Bypass Valve, 2012-2018

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 they in it for the long haul? Where the transmission is the soul of the Jeep, keeping it cool can sometimes pose a challenge. True, there are plenty of means of maintaining transmission fluid cool with external coolers, but they won't do you any good if the fluid never makes it to the cooler. That's why a sturdy thermal bypass valve is essential for the Jeep JK Wrangler, along with a myriad of other Mopar products.

Before we dive straight into our new design, let's take a look at the who, what, and why of the thermal bypass valve. First, your automatic transmission is a collection of planetary gear sets, clutch packs, shafts, and other wizardry suspended in a slurry of automatic transmission fluid, or ATF. This fluid acts as a lubricant for the hundreds of moving parts inside of the transmission. It's also instrumental in the torque converter's operation, working as a fluid clutch to get your Jeep moving from a full stop. Like most lubricants, ATF works best once it reaches a prime operating temperature range. Too cold, and the fluid is more viscous, meaning the entire vehicle needs to work harder. Too hot, and the fluid thins out too much and can even burn, resulting in irreparable damage to the transmission components.

This is where the thermal bypass valve comes into play. Think of this like an artery controller for the heart of the Jeep. In essence, this valve is like the cooling system's thermostat. In fact, the primary component is a small thermostat. Inside the bypass valve is a small thermostat that blocks fluid from the external cooler depending on the ATF's temperature. On a cold start, the transmission fluid is denied entry to the cooler as it warms to operating temperature. As the vehicle warms up, the thermostat opens and starts cycling fluid through the external heat exchanger, maintaining the proper temperature.

This valve has a different outward appearance, but the operation is the same.

In theory, the thermal bypass valve is perfect for the peak operation of the Jeep. However, the stock unit tends to malfunction, which can result in the automotive equivalent of a heart attack. The thermostat can stick closed, causing overheating in the transmission fluid, and in some cases, damaging the transmission.

We wanted to ensure that your Jeep's automatic transmission stayed safe, so we gave this valve an overhaul. Jeeps are made to be customized, so we started with a sleek and sturdy billet aluminum housing. Not only does the black anodizing add some flair, but the billet aluminum construction is sure to stand up to a typical Jeep's rugged lifestyle. The beauty is more than just skin deep as well. We installed our 160°F fully-serviceable thermostat inside our valve, which matches the factory specifications, typically found in our oil cooler sandwich plates. Our design allows for more cooling options as well. This thermostat is easily swapped with alternate thermostat temperatures, depending on the climate. For those in hotter climates or putting the transmission under heavy load, we also include a full-flow pin, eliminating the thermostat and allowing constant flow to the external transmission cooler.

From rock crawls to crawling traffic, maintaining the Jeep's automatic transmission fluid temperatures is vital. Whether you're looking for a more dependable thermostat, or you're in a hot climate and need permanent flow to the external cooler, our new Thermal Bypass Valve offers a range of flexibility and dependability for your Jeep's transmission.

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