Got a little warm today. Air temperature around 80-85, so much lower than recent weeks. Doing some mowing in Low and 4WD, up and down some moderate hills in tall grass, but not real tall. About 45 minutes in, I noticed the needle climbing. Mostly up in the high range of the white area, not into the red. I was done anyways, so I dropped in 2WD and High and headed back to the house. Pulled up and the needle was just about to the red, but not quite. Idled down to 1500 or less, opened the hood and pulled the screen. Had quite a bit of fluff, but not fully plugged. Coolant overflow bottle was mid level, not full/overflowing or empty.
Needle started dropping and settled at the blue line mid-point in the white area. Let it idle a few more minutes, then shut it down.
Didn't think to check the rear hydro connector mentioned above.
Don't have much else to do for the next few, so I may putter it around the yard a bit.