I have a 2018 f150 with the ten speed. It's not coming up to temp like it's supposed to when it's cold out and gets hot when it's warm out. Almost seems like a thermostat is stuck partially open.

 

try replacing thermostat, only motorcraft.

 

hes talking about the transmission, not coolant based on the title of the thread

OP without knowing the ambient temps, what kind of low/high temps you're seeing and in what time period kinda hard to help with a diagnosis

 

the coolant going to the transmission cooler is that same as the engine coolant. we're talking about the 10r80, not the 6r80. totally different system.

 

No. There is a internal thermostat for the 10 R 80 and it is known to have problems. I would definitely look into the 10r80s internal thermostat. not the one in the engine.

 

So with ambient temps around 32°f transmission won't usually get above 160°f with hours of driving city/highway towing doesn't matter. When it's 80°f it's not uncommon to see 230-240°f. Coolant temps usually dead center of gauge but that doesn't give a temp readout.

 

the gauges are dummy gauges they only move when things get way off.

 

There is no internal thermostat.