I have flirted with 240 pulling my 30'TT. Only gets hot in town, when it locks into final drive, may run at 200 max but depends on conditions. Without trailer 130-170 depending on the day.

Here is my Auto Gauge phantom II

 

This has been great information guys...thanks. I just finished a trans temp gauge install like Silverbullet08 and thought the thing wasn't working. Still 25-30 degrees here in Iowa and my truck has the separate trans cooler so it all makes sense now. We'll see what happens when I pull the new 30' TT this summer.