These trucks over heat and crack heads and blow head gaskets very easy. Replaced my head 3 times for simple over heating. Wasn't servere either, just a typical, "oh it's getting hot", pulled over to cool, got it home and it was done. water in oil, oil in water surely are obvious messes and no fun to clean up, but sometimes the fluid leaks into the combustion chamber and you won't notice for a while.
If your checking overheating items, don't forget the clutch fan if you have one. There is a fluid inside the clutches that is a silcon substance that creates a friction to spin the fan. This fluid can leak out sometimes, but it also can be replaced if there is a bolt fill hole. My toyota fan clutch had a refill hole, but not sure if our trucks do. I run an electric oversized fan and a thin oversized chevy radiator now. Haven't had a problem for years now. I also like a 180 degree thermostat instead of a 190 degree. Runs a bit cooler and gives you a little more time if it starts to climb up in temps.

I got fan and radiator at wrecking yard for almost nothing. Bought a fan temp relay that has a temp sensor that installs in radiator fins or inside radiator. It also has a dial on it to adjust when the fan kicks on and off. Great on hot days, I set it to run after shutting off truck for a few minutes to cool it down since restarts usually spike up high temps for a bit until thermostat can decide to open again.