I am referring to torque converter. I've dealt with this exact issue before that's why I bring it up. Before I continue on I am assuming you deleted the check valve to solve this problem not to do it and now HAVE this problem. I thought about that and it doesn't really make much sense to me to cause this issue so I'm sort of ignoring it for the time being.

The temp gun will show a few things...If output temp is very high (over 230) there is a slip issue in the torque converter, if return temp is also very high then the cooler isn't working correctly, conversely if both are normal then it is a sensor issue.

I would look first to the torque converter in this case and here is why: The dash o/d light and trans temp light turn on in sequence after a few minutes, signalling the linear increase in temperature. If it does this in town...or just tooling around it could be the pump, low flow would definitely toast the internal components. If it happens on the highway only...a stuck lock up solenoid, slipping o/d or torque converter are all possibilities.

Check your temps with a IR gun.

Report to us what they are when it's been running for a while but the lights arent on yet, and then again when they are on.

I have questions: Does it slip in O/D? Do you feel it chatter or stutter at highway speeds, do the RPMs vary without speed change? If you leave it idle in drive in your driveway does it still overheat? Does your O/D switch work? Did you connect the trans cooler line correctly? the check valve delete is for the lowest point of the cooler...if it's backwards it will not cool correctly as there are turbulators inside the cooler. Bottom to top, remember that. If your using an auxillary cooler disconnect it and make sure you can blow air through it so it's not clogged.

Let me know, I'd like to help you.

 

Just to put a happy ending to this thread: when I switched my PCM, the trans temp, od off, abs, and brake lights all went away. All your info has been helpful in finding a diagnosis to my problems. Thanks y'all