I have a `95 Explorer with the electronic four speed automatic transmission. Over the last nine months the O/D light start flashing indicating a fault code. I reset it by disconnecting the battery without bothering to read the codes. That stopped for severa months but now has started it again. This time I read the codes and I’m getting code 636 and 637 - both dealing with trans temp sensor not reading correctly.

Does anyone have any experience with this issue on this trans? Is it just a bad sensor? Does anyone know where the temp sensor is located? It is not shown in the Haynes manual as far as I can tell.

Thanks in advance for any help,

Mark

 

I have now spent more time going through my Haynes manual. It shows the trans temp sensor to be a TFT (transmission fluid temperature). In a diagram of where various sensors are located within the vehicle, for the TFT it simply points to the trans (I guess it could be inside the trans) and it states that the TFT is part of the transmission wiring harness. Therefore, it does not sound like there is a separate sensor as there is for speed or range.

Does anyone know how to fix this?

Mark

 

I'm not sure about your tranny model, my experience is on E4OD trannys BUT

TFT sensor is just a simple resistor that change its value based on temperature, it is directly solded to solenoid pack. Unfortunatelly the solution is replace the whole solenoid pack...

A friend told me he has same problem and got a faulty solenid pack in a tranny shop, removed the TFT and installed in his own package, it still working...

Once again, you have to check if this can be done to your tranny...

 

I guess that is worth looking into.

Thanks for the thought,

Mark

 

After the dealer could not find the TFT I called a trans shop locally that I have used before. They knew exactly what I was talking about and said that the wiring is part of the solenoid wiring, internal, and was relatively easy to replace once the pan was down. The insulation starts to crack with age and that causes the problem.

I then went back to the dealer and he was able to find the internal wiring harness and included in the description it states that it includes the TFT. I am going to have a regular trans service and have it installed at that time. The wiring harness is $115.

Mark

 

Thanks for the feedback, its good know that...

E4OD doesn't use internal wiring harnes since the selenoid pack provide directly a connector to outside of tranny.