The BMW ZF Steptronic already has a liquid-to-liquid heat exchanger. The transmission fluid is cooled by the coolant mixture in the radiator. We installed a transmission fluid temperature sensor in June 2005. Since then we observed that when the transmission fluid temperature reaches about 130C on the track, the transmission control module will switch to a different program. This program is not a limp mode or fail-safe mode. It simply upshifts to the next gear early even if the driver does not intervene through the paddle-shifters or shift knob.

After much white paper fluid mechanics computation, we have decided to add a secondary transmission oil cooler.

This kit is still in the test fitting and evaluation stage. A sample data is posted below.

This kit is not yet for sale.