Transmission Oil Cooler Kit, 8-Pass Aluminum, 5/16 in Lines

Heat kills automatic transmissions. Once ATF runs past about 240F it starts to oxidize, the clutch material glazes, and seals harden. The cooler built into the radiator tank is fine for commuting, but it falls behind the moment you tow, haul, or sit in traffic with a loaded truck. An auxiliary cooler ahead of the radiator is the cheapest insurance you can buy for a fresh rebuild or a high-mileage 4L60E, 4R70W, or similar unit.

This is an 8-pass tube-and-fin cooler in aluminum alloy, 15.66 x 10 x 0.75 inches. Two more passes than a basic 6-pass cooler gives you more surface area for towing and heavier vehicles while still staying thin enough to mount in front of most radiators or AC condensers. Fluid snakes back and forth through the tubes while airflow across the fins pulls the heat out.

The kit includes the cooler, CPE hose rated for 145 PSI working pressure and 900 PSI burst across -40F to 257F, mounting hardware, and instructions. Plumb it into the return line so fluid leaving the radiator cooler passes through the auxiliary cooler last before going back to the transmission. Mount it where it gets clean airflow, secure the hose away from exhaust and moving parts, then check fluid level after the first heat cycle. Confirm your vehicle uses 5/16 in cooler lines and that you have room for a 10 inch tall core before ordering.