1, i dont care how old the post is. Im still commenting on it.
2, yes, using STRAIGHT antifreeze is bad on your engine and transmission.. IF YOUR ENGINE CANNOT DISSIPATE HEAT.. THEN NIETHER CAN YOUR AUTOMATIC TRANSMISSION! Most vehicles transmission fluid flows through the radiator. It's not a coincidence that when a engine overheats and needs replaced that the transmission always seems to follow a fee thousand miles later. Your truck didn't fail you, it wasn't worn out junk as you described it. It wasn't maintenance or operated by competent owner. Sorry but it is what it is.
2, no only could your engine NOT disapate heat into the warm atmosphere from not having water but you could be the reason the head or water jacket failed because pure antifreeze * freezes * ... at -5 Fahrenheit. The water actually lowers the freezing point. It seems like you have more money than common sense 🤔