The Comprehensive Transmission Cooler Upgrade Your ’94-’07 Dodge Needs

The number one killer of any automatic transmission is heat, and the biggest killer of automatic transmissions in the diesel truck segment is a Cummins-powered Dodge—reason enough for the problem-solvers at Fleece Performance Engineering to come up with a solution. Developed for second-gen and ’03-’07 third-gen trucks, the company’s transmission cooler and line kits are specifically designed to drop directly into place and keep your 47RH, 47RE, or 48RE running cool. In true Fleece fashion, you get a comprehensive system with top-quality components, detailed installation instructions, a 1-year limited parts warranty, and a fair price. Let’s take a look at what comes in the box.

Everything You Need

Fleece offers a specific transmission cooler and line kit for second-gen (’94-‘02) and ’03-‘07 third-gen applications, so whether you’ve got a 47RH, 47RE, or a 48RE, you’re covered. The second-gen kit pictured here comes with a few more items than what the third-gen system entails, but both kits are very similar. Most importantly, they serve the same transmission-saving purpose, offering twice the heat rejection vs. stock. Key differences between the kits entail the ’94-’02 transmission cooler system’s inclusion of a transmission temperature sensor adapter block, thread sealant, a second P-clamp, and additional hardware.

A More Efficient Heat Exchanger

The transmission cooler that comes with Fleece’s second-gen kit boasts a 20-percent increase in the face area of the transmission cooler as opposed to stock, accounting for why it provides twice the heat rejection and efficiency over the OEM unit. For trucks that tow, and whether they’re stock or modified, this transmission cooler’s efficiency improvement—combined with the included high-flow lines—will keep fluid temps in check, even in the most grueling of environments. And despite the transmission cooler’s size increase, it drops directly in place of the factory piece, also mounting vertically next to the A/C condenser.

Replacement Fittings For The Transmission

Here, the supplied thread sealant is being applied to the fittings included with the second-gen kit. These -8 AN to ¼-inch NPT fittings install in the front and rear ports of the transmission case. They call for 22 ft-lbs of torque, install using a 13/16-inch wrench, and Fleece goes to great length to drive home the point of not over-tightening them—even providing the end user with the proper flats from finger tight (or flats method) torque sequence. Details like this ensure the installer has every possible tool at his or her disposal to install everything without issue.

New Fittings In, Old Lines Out

Installing the front and rear fittings that go into the transmission case calls for the removal of the factory transmission lines and the OEM fittings that once sat in these ports (the rear transmission port is shown). To break the original transmission fittings free, Fleece recommends using a ¾-inch wrench to remove the lines and a 15/16-inch wrench as a backup to prevent any damage from occurring. The fittings themselves are removed via a 15/16-inch wrench. Fleece also reminds the installer that the original transmission lines will likely need to be bent in order to be removed from the truck.

Temperature Sensor Adapter Block

Inclusion of this piece is something that differs between Fleece’s second-gen and third-gen transmission cooler kits. Designed for use in the former kit, the temperature sensor adapter block installs in the front port of the 47RH/RE and accommodates the factory transmission temperature sensor. The adapter block also accepts a -8 AN to ¾-16 male fitting that connects to the transmission line fitting, and a -8 AN straight fitting, which attaches to the fitting installed in the transmission itself. Made from aluminum, the temperature sensor adapter block is machined in-house at Fleece’s Pittsboro, Indiana headquarters.

Line Routing, Simplified With P-clamps

With the fittings in place in the transmission, the heavy-duty, ½-inch transmission lines supplied in the kit can be installed. Just like the factory lines, they route to the front of the truck by way of snaking around the engine oil pan and between the frame and radiator. Here, one of the P-clamps (and M8 bolt and lock nut) Fleece includes in its second-gen transmission cooler kit is employed to secure the lines at the front of the oil pan. The second P-clamp (and corresponding M8 bolt and lock nut) is used at the rear of the oil pan, making for a clean and tidy install of the lines.

Direct Drop-In Replacement

Fleece claims a 1.5 to 2-hour install time for its transmission cooler and line kit, and thanks to the thorough, 11-page instruction manual it provides we can picture that being the case for even the most novice of wrenchers. Here, you can see that one of two supplied 90-degree -8 to O-ring fittings has been installed in the upgraded transmission cooler on a second-gen truck. The cooler itself mounts with its outward face flush with the mounts for the truck’s A/C condenser. It bolts up in the exact same location as stock, using the included M6 fasteners and lock nuts in conjunction with a 10mm socket or wrench.

Life Just Got Easier For Your Chrysler Four-Speed

Fully installed and ready to go, ’94-’07 Dodge owners can expect cooler ATF temps across the board, whether towing, hauling, or commuting. It’s billed as the most comprehensive and efficient direct drop-in transmission cooler upgrade on the market, and we believe it. From the larger, more efficient transmission cooler to the heavy-duty, high-flow ½-inch transmission lines to the high quality AN fittings, Fleece’s second-gen and third-gen transmission cooler systems are a top-shelf upgrade in every way. And, they’re priced to sell, with the second-gen system retailing for $901.95 and the third-gen kit’s MSRP checking in at $943.95.

Written by Mike McGlothlin