I really don't know the overall condition or maintenance of your truck to speculate anymore.
And......
I never recorded the temps last year when I was driving in 100+ weather.
Maybe its time for a pan drop and change the filter and add some new fluid?
Some others have done a flush. But don't get the flush done with the chemical additives.
Just some thoughts.
Here's generic tables I found on fluid temps vs. break down of fluid over miles driven.
