Sign of Transmission issues?

Are there any tell tail signs that the transmission is on the way out? I have a 2004.5 with a auto, and have noticed that my transmission temp is running hotter then normal Everyday running around I'm showing 170-180 when it normally would sho 145-155. when I pulled my 35ft 5th wheel on Monday that my Transmission temp was just under 200 which is very high (flat land at a out side temp of 84 degrees) The only upgrade I have done is a Smarty JR which I run on the middle program. I don't feel any difference in the trucks ability to pull the load but the temp has me worried. Can you think of any other issues that could cause the temp to jump that much?