One thing i don't see in your list is a coolant temp sensor. By your description that would be the logical choice.

 

I forgot to list it, but it is new too.

 

Well, that narrows it right down.

 

This link will provide you with what you need to know to test the coolant sensor. Good luck.

https://www.bing.com/ck/a?!&&p=422cfd8f6c019827JmltdHM9MTY5MTc5ODQwMCZpZ3VpZD0yMWNkNTJkMC1iYTI2LTZiMzItMmEwNi00MWJhYmI0OTZhNjMmaW5zaWQ9NTQ0MQ&ptn=3&hsh=3&fclid=21cd52d0-ba26-6b32-2a06-41babb496a63&u=a1L3ZpZGVvcy9zZWFyY2g_cT10ZXN0K2Nvb2xhbnQrc2Vuc29yK29uK3MxMCZ2aWV3PWRldGFpbCZtaWQ9MUU2MjIzRkNGMjY5MjU5MTFEN0ExRTYyMjNGQ0YyNjkyNTkxMUQ3QSZGT1JNPVZJUkU&ntb=1

 

What has me really confused is with the coolant temperature sensor unplugged it works perfect (no code and converter locks up every time). I do not know if this will cause other problems, but with the scanner live data shows -37 deg with sensor unplugged.

What does the scanner show with the coolant temperature sensor plugged in?

The TCC will not engage and the transmission will delay shifts if the engine coolant temperature is below a certain threshold. This is done to "warm up" the engine.

A stuck open thermostat or a faulty coolant temperature sensor can cause this. A faulty coolant temperature sensor can also cause misfires and very rich mixture conditions (high negative fuel trims and rich mixture codes).

 

The temp reads about 195-200 while driving. I was wondering if the ECM is getting signals scrambled causing the TCC not to lock up.

 

The temp reads about 195-200 while driving.

Are you seeing 195-200 on an OBD-II scan tool? Or on the dash gauge?

Read the live data with a scan tool. That's what the PCM sees. The PCM uses a different sensor than the dash gauge on most of these trucks. Although your 2002 might have the LU3 engine with the dash that feeds mainly from the PCM and gets the gauge data from the PCM.

You can also check the live data for the transmission to see if the PCM is telling the torque converter to lock and that's not happening (that should set a transmission code, but sometimes doesn't), or if the PCM isn't commanding TCC lock.

Also, check for "tow/haul mode." If you have that turned on, that will disable the TCC and will go to a more aggressive shift strategy with higher shift points for a heavier load or towing trailer.

 

I just have a basic scan tool, but it does have live data and thats where I checked the temp. As far as checking the trans with scan tool, mine does not show that info. When it does not lock-up it has no codes most of the time (by using my cheap scan tool), I can clear codes and it locks up. After a couple of miles it un-locks. Sometimes it will show random misfire and other times nothing.

 

If you get a malfunction light when it unlocks, it's likely a code your tool can't read. You should also watch live data to see if your thermostat is "sticky" and opening too much and letting the coolant fall below threshold temperature for the transmission. That will unlock the converter. I've had a sticky thermostat that would just randomly lock and unlock the converter as I was driving. Usually lock after stopping at a light and continuing, then at highway speeds, it would over cool and unlock.

 

I don't get any light. The temp reading stays steady.