JK Wrangler Flex-A-Lite Direct Fit Transmission Cooler Installation

    Quick Auto Cooler Upgrade

    Heat is the enemy of any and all automatic transmission. We've been told that anything over 230 degrees will spell the rapid demise of any automatic transmission, and the fact of the matter is it's easy to heat slushboxes up. For one they are, with respect to cooling, downwind of the engine making shedding heat to the ambient air that surrounds them more difficult. Add in some hot laps through the dunes, a slow crawl through a technical rock trail in the desert, time stuck in traffic, or towing a small boat, camper, or other toy with your Jeep and transmission temperature can become a real problem. And that's all without taking the additional heat larger and heavier wheels and tires put into the system due to the additional effort it takes for the drivetrain to keep them spinning.

    Luckily we have a quick and easy solution for anyone who puts heat into the transmission of their automatically shifted 2007-2018 Jeep Wrangler JK. Thanks to the thermodynamics experts at Flex-A-Lite we can rest a bit easier knowing our JKU's transmission has a bit more fluid, and a whole lot more cooling surface area. Best part is the brand new Direct Fit Transmission Cooler (PN 31970) should have a street cost under $230 and is incredibly quick and easy to install.

    The Direct Fit Transmission Cooler from Flex-A-Lite comes with a cooler, necessary hardware, hose, clamps, barbed fittings, and a bracket that makes fitting it onto a JK a breeze. We started by mounting the cooler to the bracket following the included instructions. The bracket and cooler are made out of lightweight aluminum and the hardware to mount the cooler to the bracket is stainless steel.
    The next step is to remove the JK's grille, a comically easy task. First use a small flat head screwdriver to remove the factory plastic retainers along the top of the grille. Pry up the center and the whole retainer should come out.
    With the plastic retainers removed from the top of the grille a sharp yank will pop the grille loose from its remaining mounts. Then disconnect the right and left running light from the grille. Set the grill aside face up to prevent any scratches.
    We then dry fit the cooler and bracket to the radiator core support. You may want to pop loose a few wire loom anchors along the top of the core support. We then marked the four mounting points from the bracket onto the core support. The kit comes with four self-tapping screws to mount the bracket to the core support. We took the install one step farther installing 6mm rivnuts instead of the self-tapping screws. This is not necessary, but does yield a slightly nicer final installation.
    From here we installed the supplied hose on the cooler and fed it through and below the radiator and radiator core support. You'll have to make your way under the Jeep to splice the hose into the transmission coolant line that is feeding the radiator mounted cooler. In order to maximize transmission performance you want the fluid from the transmission to run through the Flex-A-Lite cooler first, then the factory transmission cooler, and then back to the transmission
    The supplied instructions tell you one way to determine which line from the transmission is the one that has the hot fluid leaving the transmission. We also traced the lines back to the transmission where arrows on our transmission indicated the direction of flow. We marked the arrow that indicates flow with a permanent marker to give you an idea of what to look for. Your transmission, depending on year model, may or may not have this arrow. The alternative is to start a cool vehicle and drive it a short distance and then assess the temp of the two cooling lines either using your hand or a temp gun. The warmer one should be the one with fluid going from the transmission to the factory cooler.
    Once we checked and double checked to ensure we would be cutting the correct factory transmission line we trimmed the supplied hose to length and prepared each end with the supplied barb and hose clamps. You can slide the second hose clamp onto the barb and tighten it enough so it won't fall off making it that much easier to splice these two hoses into the factory transmission line. With the two hoses pushed together move the last two band clamps into place and tighten. We then started the Jeep, got it to operating temp and topped off the transmission fluid. Reinstall the grille and go four-wheeling.