Whether your four wheel drive system is activated by a knob, button, or second gear lever; Either you’ll certainly have 4H, 4L, and N (neutral) positions marked. If your 4WD is a part time system (as is the case in most Nissan Patrols) you might see a 2H option as well.
2H is just two wheel drive, which you’ll use on the road and many smoother gravel roads. Once things get rougher though, it’s time to consider 4H.
4H or four wheel drive high range can usually be selected on the move, and can be operated at the full speed range of your vehicle. It should be engaged on slippery gravel surfaces to make your travel safer and more controllable. It saves the road surface from damage too.
In fact high range 4WD is the perfect selection for many surfaces. Firm beach sand, lightly muddy tracks, or narrow forest and bush tracks. High range gear will do it all.
Keep I mind however, that some vehicles will have a ‘centre diff lock’ which needs to be enabled to give you true four wheel drive, so it’s best to check what system your vehicle has.
Sooner or later you’ll come across deep mud, a soft patch on that beach, a rocky climb or descent, or a steep hill on that bush track. When things get tricky or technical – it’s time to hit 4L. So what does this gear mode do?
Engaging low range will increase the torque and reduce the speed of your vehicle. Therefor, everything is more controllable. In boggy sections of sand this will reduce strain on automatic gearboxes and clutches; it allows you to crawl through the sand with less effort.
On a steep hill climb, you want to keep it slow and steady without stalling. Especially those boulder laden ones where dented panels are a danger! The increased torque will allow you to take it easy and practically idle through the rough stuff.
Coming down the other side; low range slows the vehicle down and enhances engine braking – so you’re not working that brake pedal too hard.
There are of course limitations to what you can do in low range. Exceeding 40 kilometres and hour in low range is a big no – as driveline damage can occur. And in many vehicles, switching between high and low range can only be done at a stand still (unless you enjoy the sound of grinding gears).
Now that you know the theory behind high and low range gearing, practise will make it an instinct! So throw on your set of Rhinohide, get out there – and explore!