Well you know going 80 on the highway and you hit a grade the temp wants to climb a little bit. That happens with my 4.9 Xl. My 302 XLT is almost just the opposite. I have a four core brass and copper radiator in it. City driving the temp wants to drop a little bit when the thermostat opens. It seems to do too good of a job cooling.

 

Now imagine 80 on the highway with a 4,000 lbs pontoon boat, I say far game if the truck gets a little warmer, it's working hard up that hill, not so much because of weight, but a lot of air drag. I've towed heavier things that felt lighter on the interstate. Maybe I need a bigger radiator, did the tow package have a bigger radiator, I have the tow package but was wondering.

 

If you have an OEM tranny cooler you for sure have the tow package. I don't think the radiator was any different though. I installed the biggest one I could find when I upgraded my heads. I've decided it's overkill for what I use the truck for. O well.

 

OK, I thought it was some kind of barometric pressure thing. Like high altitude cooking or something. Most any vehicle will run hotter under a strain, I was just talking of change during normal driving.

 

I do have oem tranny cooler, it's not very big though. I need to put a temp gauge in for my tranny to make sure it doesn't get too warm. My radiator seems to be a respectable size though, and driving unloaded the gauge doesn't budge.