Join Date: Dec 2013
Location: Seattle WA
Vehicle: 2000 SLK 230 Sport
Other Toys: Yes (cars, bike)
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Transmission fluid temperature control upgrade
I always said that a kick in your behind is a step forward; same this time, only with some hours to spend on the car…
I always had on my mind to detach the transmission line from the radiator and most so because it is a known issue that the cooler radiator insert tends to brake. I did not follow common sense and got kicked in the very same spot I mentioned earlier. The bypass broke… Nothing bad happened besides the transmission fluid getting into the cooling system (due to higher pressure in the transmission it’s not possible to get water into the transmission…). Cleaning the entire cooling system is something if done right will take about 10 hours, multiple times installing and removing the radiator and the expansion tank… Since this posting does not regard the cleaning process I will go straight to the upgrade, but not before mentioning that my almost new transmission fluid, filter and gasket had to be replaced as well.
The radiator got two caps instead of the transmission lines and was kept in place. The transmission lines have been modified to accommodate a thermostatic control unit which does a bypass until it reaches 80 C, at which point it will allow the fluid to circulate thru a transmission cooler. Once the fluid is just under 80 C the bypass opens again and so on… This system will make sure you don’t operate at any other temperature than optimum, keeping the fluid level in the sweet spot.
The photos show the installed cooler, the control unit with the lines attached to it. The whole system is made in USA and is sold as a performance kit. The kit comes with a fan and a temperature sensor which will turn the fan on and off, however if you want better performance and faster heat-up times you disregard the fan and get a control unit as I did.
I hope this will help some people here and good luck!