It was pointed out earlier that most 4x4 trucks can handle most types of off-road driving, and most climates, too.
But what if you're off-roading in the Alaskan tundra? Or hauling a trailer full of ATVs in Death Valley? If either of those situations applies to you, there's a kit to help you in your off-roading insanity -- whether your adventures take you to very cold or very hot climes.
Some manufacturers offer a cold-climate package, which usually includes a more powerful battery for cold starts, a higher-output alternator and a heavy-duty starter, too. If you're going to be in an area subjected to extreme or extended cold temperatures an engine block heater will keep the engine warm for an easier start. Once the truck is up and running, the heat from the engine will keep things toasty.
At the other end of the spectrum, you might want to add a transmission fluid cooler, especially if you're towing anything or if the transmission is otherwise under extremely heavy load. Again, some manufacturers offer a package to deal with just such a situation, with a transmission cooler and a larger radiator to keep the engine from melting into the sand.
All these things keep the truck happily humming along, so let's take a look at the systems in 4x4s that keep driver and passengers safe and sound.