AT Oil Temp light, vehicle shuts down, then restarts!

[cmyers]

2000 TLC with 87,500 miles.
This is the second time that I've had the AT Oil Temp light come on. When I drive a little further (<2 miles) the power gets sluggish, almost like the torque converter wasn't doing it's job. Like I said, this is the 2nd time it has done this. The first time, I took it into the transmission shop. They tore it down and found it was worn, but nothing obviously broken. I had the go ahead and do a total rebuild (was fearing the worst of the known MY 2000 trans issue, and decided to "invest" in my truck since I plan to get 500k miles out of it).

When the light comes on, it actually flickers (something like you would see if there was an intermittent grounding issue). If I take it out of overdrive, light goes off for a little bit, but then comes back. As soon as I turn O/D back on, truck dies.

Oddly enough, after it died, the starter would engage and attempt to restart. Sometimes it would, others not. Now, after having it parked for several minutes, key off, key out. Then putting the key in and turning to "ON" to see if AT Oil Temp light was still on, after several seconds, the starter would automatically engage again and start the truck!!! Do I have a ghost???

Any ideas? I'm sending to trans shop again to verify that the trans is good and that they didn't screw something up.

 

[Sligex]

I question what your temperature sensor is actually reading. It could easily be a corroded/faulty connection causing a mis-read thus causing your light to flicker. You should be able to get your temperature through the OBD2 port, whether you use a Mini-VCI or a Scangauge/Ultragauge.

I know for a fact that the truck will NOT let you start it if your A/T temperature is too high. Are you sure your transmission cooler is working properly?

 

[cmyers]

Thanks for the response. I'm pretty sure the transmission cooler is working, it was installed new in June/July and is slightly oversized from stock, but I can only assume. I too question the integrity of the oil temp sensor. I have also wondered about the wiring to the actual indicator. This morning, truck was 100% normal. I tried to force the light to come on again by driving around, revving engine in Drive with brakes on, but still nothing. I also got into the wiring behind the glove box where the connectors are for the signals to the indicator and the ECM, but couldn't cause the light to come on, so probably not a wiring/corroded connector there. Still possible on the actual sensor though.

I find your comment interesting that the truck will NOT start if the A/T temp is too high. That would lead me to believe that the actual temp and what the sensor was sending was NORMAL, because the truck would start. In fact, it would actually crank all by itself, with the key ON, but without turning the key to the START position. That was a little freaky. There is really not much in the starting circuit, so there isn't much to go wrong there or cause the starter to spontaneously engage. I think I'm chasing two problems, unless there is actually an issue inside the ECM that could be causing such odd behavior.

 

[Sligex]

OK, I just checked the thread where I got my original no-start information from (https://forum.ih8mud.com/threads/transmission-overheated.814905/#post-9321486) and it looks like he was having the same thing where the truck will crank, but not actually fire to start. He however is running an '06 (VVTi)

When you say, "it would actually crank all by itself" are you referring to the condition where you turn the key to the start position but don't have to hold it there for the truck to start? I believe that may be a feature on some of our trucks, but I'm not entirely sure whether it's a feature on the older 100's. It would make sense for the truck to keep trying to crank itself until it "started", until it eventually gave up and stopped trying.

I believe the transmission oil sensor reads somewhere near the torque-converter/some extremely hot area of the car. You were complaining of a "sluggish" feeling problem like the torque converter wasn't performing 100%, what could be happening is your torque converter is failing and thus introducing extra and unnecessary heat to the transmission oil, thus causing the A/T overheat condition. Have they rebuilt/checked your torque converter?