4L80 overheating

[Billl70]

I have a 70 C10 with the following; 383 stroker with fuel injection running 373 gears pushing about 530 hp with a newly rebuilt trans from a guy that knows what he is doing. also have TCI computer on it to keep everything right, we have gone through everything that we can think of, also running dual fans and a trans cooler with fan all running at the same time and this damn thing still overheats. Can start out cool but when I go into overdrive it starts heating up, yesterday I ran it and it got to 207 degrees and engine was at 185, we are at a lose as to what's causing this. Can u please give us some idea as to what is causing this. Thanks in advance for any help. Billl70

[carkhz316]

Is the torque converter locking up properly? Also, how high of a stall if not a stock style converter? Out of lockup, the 4L80 seems to run hot due to fluid shear. In my '03, when I had some misfire issues that would keep the trans out of lockup (P0300), it would run around 200* under no load besides highway driving.

[davester]

Maybe check that fluid is running through the trans cooler (ie, that the lines are getting hot).

 

And for my truck, when I need to check the trans fluid level, I drive around for a bit with the trans in a gear lower than it should be, I find that heats it up faster.  Maybe you're driving around in too low of a gear?