hey all im wondering which line is the hot line coming out of the 48re? i had a temp gauge installed on my truck by a local shop and they put it in the rear line. Is that right i thought the front line is the hot line?

 

Front line is the hot line, rear line is the return line.

 

thanks im going to have to Edit to the local shop they told me they put it in the hot line coming out of the tc

 

They cross. Look again. Is it the front line COMING OUT or the front vertical line? I looked and looked... I put my "true temp" on the rear VERTICAL. I will have to double check tomorrow, but all the "replacement" lines looked like the one I attached to...

I believe that it is the rear VERTICAL line.

 

Maybe this will help, got it from Diesel Manors instruction sheets under support.At the point of the arrow it is the rear line,but maybe they cross above ,it is not too clear in the photo.But you can see where they installed the tee.

 

Best way to tell if your unsure is start the truck when cold and feel the lines.
Have someone you trust hold the brake and block the wheels with the ebrake on and put the truck in drive will show quicker results.

 

its the front line coming out of the trans, just swapped them and now my temp are about 30-40 degrees higher

 

You could also check line temp. if you had an infrared temp probe.Best way is to probably just do a slight warm up drive and check by hand as said above.