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2007+ Jeep Wrangler JK Transmission Cooler

Posted in How To: Transmission Drivetrain on July 1, 2011
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Last year, 88,000 JKs were recalled for potential automatic transmission overheating. You might think that the fix was to install a transmission cooler or some other mechanical upgrade to better control the transmission temperature. Nope. When you roll into your dealership for the recall, they install a trans temp idiot light, and they instruct you to pull over and park your Jeep if that light ever comes on. Right.

For right around $50, we came up with a solution that we feel a whole lot better about: adding a Flex-a-lite transmission cooler. Part number 4118 fits nicely behind the grille, and with a GVWR rating of 18,000 pounds, it’s more than triple the cooling capacity that a JK should ever need. This cooler is made in the U.S. and features Turbulators—twisted inserts that increase heat transfer from the ATF to the copper tubes and cooling fins.

The Flex-a-lite cooler included push-tie mounts, barbed fittings, hose clamps, and a length of rubber hose. To mount it in a JK the way that we show here, you’ll also need two 3⁄8-inch fittings with barbed ends on both sides, two extra hose clamps, a couple of more feet of 3⁄8-inch rubber tranny cooler hose, and about three feet of steel strapping. Fitting the cooler to our Jeep was a snap, taking just over two hours, and that was with custom mounting work for a super clean installation. Even if your JK wasn’t affected by the recall, this is an easy and inexpensive upgrade that can extend the life and performance of your automatic transmission.

We took some rough measurements of the space in front of the grille and found that a Flex-a-lite 4118 would fit well. This is a six-pass cooler that measures 7½x15 inches overall. You can mount the cooler vertically or horizontally, but don’t mount it with fittings facing down. In a JK, the most natural way to mount it is with the fittings facing the driver-side headlight.
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Flex-a-Lite Consolidated
Milton, WA 98354

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