I think Quintin stated that our trucks have a 180 deg. tstat in the trans line that acts like a bypass or closed loop to flow the trans fluid from the trans to the switch(located by the bellhousing) back to the trans until temps reach 180. My question is, for a fluid flush would this switch just allow the fluid in the lines and cooler to be changed? because the temp is not high enough to open the TTS and thus allow fluid flow from the trans and TC to the front. I know on my truck at idle the trans temp bearly get over 160, and only seems to hit 180/190 in heavy stop and go traffic.