Have a code of P0713 A/T temp circuit high. Something to that nature.
Went to a shop and they hooked up a Tech 2 and overrode the electronics and it would not shift into 4th so he said take the pan down and see whats in it....Well, nothing just a little wear in it. Smelled good.
It was rebuilt 8,000miles ago and the guy who rebuilt is says it's the trans wiring harness with the temp sensor? anyone have any comments or Ideas? I did clear the codes and drove it and that same code came right back......would not shift into 4th after clearing codes.....Please help.....

Replace the Transmission fluid temperature temperature sensor. Easy to do and inexpensive to replace. Not the wiring harness unless they tested the wiring haress. L and M pins I believe.
Resistance check and check the stickies..;)

I can't find just the temp sensor....They have to sell them together for some reason......Do you think that is for sure the problem? Since the code is there? thanks...

They sell the TFT sensor and the wiring harness together to remove the possibility of Grounding or Shorting within the wiring harness.
Your problem to me indicates just this very thing.
The wiring harness is unmistakenly easy to replace. You cannot make a mistake in replacing and reattaching to the 1-2, 2-3, TCC solenoid, PCM AKA force motor aka stepper motor.
Buy the whole thing and replace the whole shebang.
If you don't want to here's what you do.
Get a Infrared temp gun after driving the truck around the block. Park the truck. Disconnect the connection and find pins L and M. Check resistance and use the temp gun to get a temp from the bottom of the pan.


http://www.dieselplace.com/forum/showthread.php?t=198758#post2386853


Fahrenheight column is self explanatory and then match minimum vs maximum. Nominal is between and practically means nothing. Nominal could be anything in between. Good luck
http://i120.photobucket.com/albums/o187/USMILRET/4L80E%20Transmission/TFTResistanceChart.jpg

I took the wiring harness out already and ordered one from the local Chevy dealer and will have it tomorrow. SO I will drop it in and see if that does the trick......Sure hope so. I just dont see it being mechanical when there is no trash in the bottom of the pan and no tranny noise. I do hear a sprag every now and then.......Not sure if thats going to hold for long...Thanks for the info that is a good chart......

interested in buying a 94 yukon 6.5 turbo diesel, 2 door, 129,000 miles clean no rust what so eva,nevada vehicle for 2000 thousand bucks. only thing the owner said is wrong is no overdrive because of tranny cooler damaged it. tested and drove truck everything fine just no overdrive, anyone know of this please help me make a wise choice?

interested in buying a 94 yukon 6.5 turbo diesel, 2 door, 129,000 miles clean no rust what so eva,nevada vehicle for 2000 thousand bucks. only thing the owner said is wrong is no overdrive because of tranny cooler damaged it. tested and drove truck everything fine just no overdrive, anyone know of this please help me make a wise choice?
okay

Damaged cooler will cause restriction. Restriction causes heat. Heat causes no OD. Possible cause..