Hi, I just installed a digital trans temp gauge. My work trailer is about 2,800 lb's, my truck is an '04 cc xe 2x4. I was on the Hwy last night and noticed if I run in 4th (as I allways have) the temp. reads mid. 140's. Now if I drop it into 5th the temp drops to the low 140's and high 130's. Is it safe to run in 5th on the Hwy as long as the trans temp. stays low or will it hurt somthing towing in 5th ( I use 4th for hill's).