Ok, yeah, that's the check valve alright. It looks like the cooler in the radiator has been completely bypassed...... There IS an external cooler, right?

 

well sheet, it goes somewhere between the radiator and the grille in order to recirculate the fluid, but I didn’t check to see if it goes into another cooler or if it just bypass the cooler completely…I’m driving right now 🤦🏻‍♂️ but I’ll check after

 

If you have one of the 'heavy duty' packages, or towing package, there will be an aux cooler between the radiator, and a/c condenser.

 

that sounds like my truck..per the repair manual for this truck, it sounds like replacing the torque converter might be the next step

 

I would be more tempted to plug in with a scanner, and see what the PCM thinks trans temp is when it is stone cold. How long between startup, and the light coming on?

 

I took it to oreilleys a few weeks back and scan tool didn’t show anything, maybe a trip to the local garage would work out better.

The trans temp light will come on sometimes within a minute to a few minutes while it’s still warming up, but sometimes it’ll drive for twenty minutes before it dings.

 

That sounds like an electronics mismatch..... Might try changing out the governor pressure sensor and solenoid, see if that doesn't solve the issue. Will also need the correct retainer for one or the other, can't remember which....

 

I thought that might be something to check, but it looks like I got to drop the pan to replace it. I’m gonna take it to the garage in the next few weeks, I’ll update here.