Blue65

I replaced the transmission tstat with Superior transmission part# STP-STL010. Works great. Steady Temps of 150. Thanks for the help.

Thanks guys. I think everyone can agree I need to go ahead and remove the thermostat on the transmission line. I am assuming that is on the return line back to the transmission? I guess I need to do a bit of research on where that thermostat is located. Thank you again.

I am going to start towing a 3k # boat regularly. I am looking at getting an aux. transmission cooler as well as a lower temp thermostat. It looks like for my year model truck the thermostat is a combo, of the housing integrated to the actual thermostat. Can anyone tell me which thermostat is currently in an unmodified 2018 Sierra 5.3L Direct Injection? Which thermostat would you guys recommend? I live in Texas along the gulf coast, so it gets pretty warm down here. In regards to trans coolers. I was looking at the Mishimoto one. It is super nice especially since it comes with all the clean brackets. However, that comes with a price tag. I was wondering if anyone here had other suggestions on trans coolers. Thank you in advance!