Derale 13503 Series 8000 Plate & Fin Transmission Cooler

Heat is the number one killer of an automatic transmission. Push the fluid past roughly 220F and the additive package starts breaking down, the clutches begin to slip, and every 20 degrees over that range cuts the life of the unit roughly in half. The Derale 13503 is an add-on cooler you plumb inline with the factory transmission cooler lines to hold those temperatures down when you tow, haul, or crawl through summer traffic.

This is Derale's Series 8000 plate-and-fin design. Each tube has embossed turbulators pressed into it that stir the fluid as it passes through, so more of it actually contacts the cooling surface instead of sliding straight through the middle. The whole core is furnace-brazed aluminum for a leak-resistant, one-piece structure, finished in black, and the cooling fins are protected by extruded plastic fin guards that keep them from getting crushed or flattened during install and use. At 2.5 pounds it is light enough to hang off the front of most radiator supports without extra bracing.

It ships as a kit with hose, clamps, and universal mounting hardware, so you are not chasing down extra fittings to get it on the vehicle. Mount it ahead of the A/C condenser or radiator where it gets clean airflow, run the transmission fluid through it in series with the stock cooler, and top off the small amount of fluid the added lines hold. Because it is a universal add-on rather than a direct OE replacement, it fits a wide range of trucks, SUVs, and tow rigs regardless of transmission model.

Anyone towing a trailer, running a heavier tune, or living somewhere hot who watches their trans temp gauge climb under load is the buyer for this. Adding cooling capacity is the cheapest insurance you can put on a transmission you plan to keep.