I'm going to buy Torque app and see if I can diag the torque converter with it.

Well if you tap into the wire for the lockup, you can manually lock it up wile in gear with your foot on the brake, if it kills the truck it's working. If not, well, it's not working. Idk if it's really the best way to test it, but it's one way to do it.

I can't remember off hand what wire it is but if you do a search I'm sure it's a easy find.


Or if your running down the hwy in OD, get to a point where it will down shift, it'll downshift than it's almost like it will do a half shift when the converter locks back up.

At this point I'm going to wait to diag the ICP and torque converter until I get the Torque pro app. I have 2 iphones, I will switch one to a Samsung Galaxy (I will buy one within a week) With torque app I can watch the ICP voltage and figure out right away if its the wiring, or watch the ICP gauge and see if its a bad ICP sensor. Torque pro app also has TC slip guage, so why play around? When I can figure both out with that cool app. Will update in 4 days when I got the new Samsung Galaxy s5 and obdII blue tooth adapter.

I believe Mark K mentioned OD being part of the cooling circuit on a 4R100 transmission.

OP 188° cruising seems high to me. I wasn't getting that high until a mountain pass doing 70mph without the OTW cooler.

Took the truck out into the country to visit parents, drove 45 minutes at 67 mph, 99 degrees out side, tranny temp hit 212 degrees, obvious problem here. I have also noticed since I flushed the tranny with new fluid the torque converter cover weep hole has fluid dripping out of it, I wonder what is leaking up there, a shaft seal? the converter it's self? I'm still Waiting on the new Samsung galaxy S5 to ship in from Amazon so I can get Torque pro app for droid. Check engine light kept going on and off during the drive too (ICP). I plan to just park the truck till the phone show's up. I still plan to diag the ICP and the torque converter with it, if it's a bad torque converter I really don't want to tear down the transmission to find the problem. If it is a bad torque converter, I might as well do a rear main seal while I got the tranny out.

Torque converter seal, you probably need the newer Viton version.

I read about that newer version... thanks!

-Ok, got new phone, got torque pro. Determined ICP was reading 0.0 Voltage.. swamped wires around in different combos until voltage hit 0.5v (KOEO) and I think 3.1v while running. Check engine light is now gone.

-Transmission issue.. I am not sure what the TC slip should be compared to the Engine RPM I made two videos for you guys to watch my numbers..
tell me what you guys think!

on ramp to highway video 1

I maintain speed better in the second video.. shouldn't the Torque rpm and engine Rpm be much closer when crusing?
Look at the video screen shot below you see a big difference.
highway video 2

Also I am not getting a coolant temp or Engine oil temp.. is this torque or an issue with the actual sensors? Coolant dummy gauge seems to be working..

TC slip is the difference in RPM from engine speed to torque converter output (transmission input) speed.

No, they should be very far apart when cruising. The only time they will be the same is with the trans in gear and the truck stopped. When the truck is stopped and the engine is idling in gear the output of the torque converter is zero and the input is the same as engine speed. So slip across the converter is (engine speed) - (output speed) = engine speed.

At cruise speed TC slip should be zero, +- about 10. Your's never gets anywhere near zero, which says that the torque converter isn't locking. That's why it is running hot.

Thank you Mark, I am relived to have this issue diagnosed. I will buy a stock converter and replace it. I will post pics and some of the process, for others to learn. Once again thank you!

If that doesn't fix it, and there is a good chance that it won't, come back here and I can help with diagnostics.

Or you could do diagnostics BEFORE buying the converter. The converter may or may not be the problem.

I will buy a converter anyways so it can be ruled out. I will order one next week, already drained pan and converter, anything else to check while I am pulling the transmission out? (is there anything physically to inspect on the solenoid?)

- I installed a new brake switch a few months ago. (Neutral park safety switch), Truck would not shift out of park one day.

$20 it's the brake switch causing no lockup.

That's very unclear. Did you replace a switch on the brake pedal, or a sensor on the side of the transmission?

Switch on Pedal. I named the wrong switch in the above post.