Mishimoto MMTC-JL-18SL Transmission Cooler

Keeping your 2018 and up Wrangler JL transmission temps low is no challenge for the Mishimoto MMTC-JL-18SL transmission cooler. This cooler features a large 11-row plate and fin design that is a 100% complete, direct fit kit with all necessary hardware to allow for mounting right behind the grille.

This Mishimoto transmission cooler is features an additional 83% fluid capacity which allows for the use of an extra 0.5 quarts of transmission fluid.  

Mishimoto MMTC -JL-18SL Transmission Fluid Capacity Over Stock - Transmission Cooler Guide

Like all direct fit, vehicle specific Mishimoto transmission coolers, this will fit your Wrangler JL without any major modifications with basic hand tools in an hour or two depending on your skill level.

Mishimoto MMTC-JL-18SL Transmission Cooler Specs

Mishimoto MMTC-JL-18SL Transmission Cooler for 2018+ Jeep Wrangler - Transmission Cooler GuideThe Mishimoto MMTC-JL-18SL transmission cooler comes with all necessary installation hardware, which isn’t much, just 4 spacers and some screws. This makes for an extremely simple installation. 

After installation, you can expect to see a 35-40 degree drop in transmission temperatures.  

In addition, this cooler provides for an extra .5 quarts of added fluid capacity. Based on this, you will need an extra quart of transmission fluid. 

Cooler Core Dimensions: 19.44″ x 4.21″ x 1.25″

Cooler Type:  Plate & Fin

Cooling Rows: 11

Installation Kit: Built in distribution block designed for stock lines. 

Mishimoto MMTC-JL-18SL Pros & Cons


  • Large, Efficient Design
  • Complete Installation Kit
  • Direct Fit
  • Lifetime Warranty


  • N/A


For the cost and simplicity, the Mishimoto MMTC-JL-18SL transmission cooler is hard to beat for your 2018+ Wrangler JL.  With its direct fit and easy to install kit, this cooler has our vote for one of the best Jeep Wrangler JL transmission coolers available, and was recommended in our Jeep Wrangler transmission cooler guide

As with any  transmission cooler installation, we always recommend that you purchase an additional quart or two of transmission fluid to take into account the increased capacity the cooler and new lines may provide, as well as any spills. 

Once your new MMTC-JL-18SL cooler is installed, it is highly recommended to check your transmission fluid level to make sure you are still within a safe range.