Mishimoto Transmission Cooler, Silver (MMTC-DMAX-17SL)

A direct-fit replacement for the factory transmission cooler on the 2017-2019 L5P, built as a 13-row stacked-plate core to pull more heat out of the Allison's fluid.

why this one — Pick this over a bar-and-plate cooler if you want the easier install and a warranty you can actually use, since Mishimoto rates it an easy install and backs it with their lifetime warranty. Two honest catches: Silverado grilles need minor trimming to clear it, and Mishimoto publishes core volume and fin area gains but no measured temperature drop, so you are buying on spec sheet rather than test data.