Just curious on where is the return line and supply line on a 42 re transmission are located trying to make sure I have this installed correctly

 

Line at the front is Out to the cooler, line at the back is return from the cooler. There is a check valve in the out line, just in front of the engine, where the line changes from metal to flexible.... That needs to go. They like to clog, and then your trans burns up.

 

update I bought an infrared temperature scanner and found out that my transmission temp light come on at 90 degrees and has a constant max temperature 150 replaced all the electronics on the inside and the computer and it is programed for my vin number I'm not even sure if it is possible to get the transmission temp that low. any ideas of where I can start

 

What exactly is the issue you're having? According to the interwebs, "The ideal operating temperature for transmission fluid is between 175 and 225° F. This range balances fluid viscosity and heat." Trying to get your tranny to run cold is not optimal either.

 

the temperature light is coming on and takes it out of o/d. I don't understand why it's coming on when it shouldn't come until of a temperature of 220

 

Had any transmission work done recently?

 

If your temp gun is in celsius, that sounds right for the light coming on at 90C (around 190ishF mental math rounding), 150C is 250+F and that would be melting soft parts inside the transmission.