Has anyone tried replacing the plunger rod inside the valve with a slightly different length rod to reduce the regulating temperature? (Assuming you have a valve not too corroded to work with). It appears to me that would be an easy and free solution to reducing the opening temperature.
I am thinking of replacing the rod with a slightly longer rod fabricated from a drill bit shank of the correct diameter. I might start at about 1/16" longer to see how much that would change the minimum temperature.
The consensus I have read about transmission temperature seems to indicate about 160 degrees is ideal. That correlates with the 158 degree opening temperature of the newer GM part.
For us that live in colder winter climates, we want the fluid to warm up to operating temperature quickly and not remain too cold. That is something that won't happen if we just bypass the thermostat. After all, GM wouldn't have gone to the expense of adding a thermostat unless there was an advantage to it. Simply bypassing the thermostat doesn't make sense to me.
on my 18 it gets plenty hot without a thermostat, unless you live in -00 or less degree weather 24/7 then it won't ever be a problem
mine has no thermostat, additional 40k cooler, deeper trans pan with 3 extra qt's and it still hit's 190 if I push it
typical temps on mine is around 145-165 but I can make it go higher.
stock it was hitting 210-220 driving normal (for me) which would be like you are 30 minutes late to your own funeral for others.
my 2012 has the same setup, winter time it will sit at the same temps 145-165, but in the summer even just idiling it will sit at 180 and will flucuate up/down a bit depending on how I drive anywhere from 165-190, I did have it hit 225 once up at high elevation and slow traffic around 6000-8000ft and 85deg ambient
I did have to move the trans cooler from in front of the radiator because it was making the engine run hot
all of the above probably does not apply to all of you that drive normal or like gramma with no where to go and no place to be in the gazillion hours and persist to drive the speed limit with no care in the world and could care less about all the traffic behind you.