The ZF 8-speed transmission found in the 2021+ BMW G8X M3/M4 is a stout and snappy unit that's capable of withstanding the onslaught of torque brought on by the S58 engine it's mated to. Add a tune and some bolt-ons, and the stock cooler just can't keep the ZF 8HP safe. This inadequacy can lead to high transmission oil temperatures, sluggish shifting, and potential transmission damage. Fortunately, the engineers at Mishimoto have developed a transmission cooler to maintain optimal fluid temps and keep your ZF 8HP running in peak condition.----The Mishimoto 2021+ BMW G8X M3/M4 Performance Transmission Cooler excels with its impressive 41-percent increase in core volume, delivering superior cooling efficiency compared to the stock cooler and keeping your transmission cool even in the most demanding driving conditions. This transmission cooler also offers a generous 17-percent increase in fluid capacity to increase the cooling potential of the entire system. Internal cooling fins increase the surface area in contact with the fluid to improve heat transfer and efficiency. The dual-pass design keeps fluid in the cooler longer, removing more heat without affecting airflow to other cooling components behind the transmission cooler.----High fluid temps aren't the only worry on the track or the road; your trans cooler sits front and center in the grille, taking every hit from road debris. That's why we've included a durable steel stone guard to protect the trans cooler and keep fluid where it belongs. Installation is quick and easy, as no modifications are required. Like all Mishimoto products, the Mishimoto 2021+ BMW G8X M3/M4 Automatic Transmission Cooler comes with the Mishimoto Lifetime Warranty, providing peace of mind and confidence in your investment.