the HDJ81 has only the tranny line through the bottom of the rad for cooling, you might want to consider the aux tranny cooler.
the gasser 80s in most countries have the factory aux cooler.
it was an eye opener when i realised the JDM didn't have them. You might want to talk to Seldon at G&SCruiserparts or Mike at West Coast Cruisers for their suggestions.
a Pyro tells you how hot the exhaust temps are, you will be surprised at how fast the pyro moves. It can move as fast as your tach on a diesel, unlike the water gauge that basicly tells you to "pull out your wallet" when it hits the red.
i recommend them to all my customers and i run them in most of my diesel trucks. they truely are a head saver.