CSF Cooling High-Performance Transmission Oil Cooler 2021+ BMW M3/M4CSF Cooling has developed a High Performance Transmission oil cooler for the 2021+ BMW M3 M4, designed to allow the cooling system to keep up on modified tuned vehicles, especially track and competition cars. Transmission oil temperatures have a major impact on the shifting performance of the automatic transmission. These rising fluid temperatures cause delays in shifting. While sluggish shifting is frustrating, the larger concern is the possible