Low-range basics: when to actually use it and why your rig needs it working

Pulled up behind a bloke on the Oodnadatta Track a few years back, stuck at the edge of a washout with his rear wheels spinning like a poker machine. High range, foot flat, revs screaming, going nowhere except deeper into the hole he was digging. I wound the window down and asked him if he'd tried low range. He looked at me like I'd suggested he try flapping his arms. "Thought that was just for rock crawling," he said. Denise still brings that one up.

Low range is the single most under-used feature on most tourers' rigs, and I reckon it's because nobody ever properly explains what it's for. The owner's manual gives you a paragraph and a warning symbol. The bloke at the dealership shows you where the lever is and moves on to the sound system. So people either never touch it, or they touch it at the wrong time and wonder why the diff howled at them.

What low range actually does

Low range isn't a speed setting. It's a gear reduction that sits between your gearbox and your diffs, multiplying the torque getting to the wheels while dropping your top speed right down. Most 4WDs give you somewhere around a 2.5:1 to 2.7:1 reduction in low range, though it varies by model — a 200 Series Cruiser and a Patrol won't have identical ratios, and neither will a Ranger or a Triton, so don't assume your mate's numbers match yours.

What that means in practice: first gear low range might only get you moving at walking pace, but it'll do it with far more twisting force at the wheels than first gear high range ever could. You're not going faster in low range. You're going slower, with more control and more grunt, and that's the entire point.

High range is for driving. Low range is for managing terrain where wheel speed is your enemy and traction is scarce — steep descents, soft sand, rocky climbs, deep mud, washouts like the one that bloke on the Oodnadatta found himself in.

When you actually need it

The honest answer is: less often than people think, and more often than that bloke thought. On a groomed track like the Birdsville Track in good conditions, high range four-wheel-drive is doing the job most of the time. You'd want low range for the sandy sections if your tyre pressures are down and you're crawling through loose stuff at low speed, or for any steep, rutted pinch where you need to keep the revs low and the wheel speed controlled.

Steep descents are where low range earns its keep and where most people skip it out of laziness. Going down a loose, rutted grade in high range means riding the brakes the whole way, which heats them up and can lock a wheel on loose surfaces — that's how you lose steering control on a slope you really don't want to lose it on. Low range with a bit of engine braking, foot mostly off the brake pedal, keeps your speed low and steady without cooking anything.

Deep sand is another one. If you're bogging down and your instinct is to plant the accelerator in high range, you're just digging a hole and heating a diff. Drop to low range, second gear usually, keep the revs a bit higher than idle, and let the torque do the work at a lower wheel speed instead of spinning your way into the Simpson. Speaking of which, anyone planning a crossing of the Simpson Desert French Line will be using low range plenty on the steeper dune faces, particularly heading east to west against the grain of the dunes.

Rock and rutted climbs, obviously. River crossings where you want a controlled, steady pace rather than a burst of speed and a wall of water over the bonnet — that ties into a different skill again, and if you haven't read our piece on how to read a 4WD water crossing before you commit, that's worth doing before you need it, not after.

Where people get it wrong

The classic mistake, and I've made it myself more than once early on, is trying to select low range while you're moving, or while the vehicle's under load with the wheels turning. Most modern 4WDs need you stationary, foot on the brake, transmission in neutral, before the transfer case will shift cleanly. Some will let you shift on the fly under specific conditions, but check your handbook rather than guessing — an incomplete shift can leave you with a transfer case stuck half-engaged, and that's a tow truck problem in a place you don't want a tow truck problem.

The other one is using low range as a substitute for tyre pressure and technique instead of a companion to it. I've seen people crawl through soft sand in low range at pressures still sitting at highway numbers, wondering why they're bogged anyway. Low range multiplies torque; it doesn't create float. You still need to drop your pressures for sand and sort your technique — our piece on corrugations and how to actually drive them covers the pressure side in more detail, and while corrugations aren't the same problem as soft sand, the underlying lesson about matching pressure to surface applies just as much.

And then there's the opposite mistake: leaving it in low range longer than needed, which is mostly harmless but does mean you're grinding along at 20 km/h on a section you could safely do in high range, burning time and fuel for no real gain. Once the terrain opens back up, shift back.

How to tell if yours still works

Here's the bit that actually matters for touring, and it's the reason I'm writing this at all. A lot of grey nomads buy a 4WD, tow a van up and down the east coast for years without ever leaving bitumen or a graded gravel road, and never once engage low range. Which is fine, until the day you're on the Gunbarrel or heading into Gibb River Road country and you go to select it and something's not right — a linkage that's seized from disuse, a transfer case seal that's perished sitting idle, or an electronic selector motor that's given up because it's never been exercised.

My rule, and I'd argue every tourer heading remote should adopt something similar: engage low range and drive a few hundred metres in it every few months, even on a flat gravel car park if that's all you've got. It costs you nothing and it tells you the transfer case is actually shifting, the selector's working, and there's no grinding or clunking that wants attention before you're four hours from the nearest town. I do it before every big trip, without exception, usually in the driveway before we've even hitched up — cheap insurance against a expensive surprise.

If you're planning anything on the Anne Beadell Highway or the Gunbarrel Highway, where a transfer case fault could leave you stranded a long way from help, get it checked by a mechanic who knows 4WDs specifically, not just your general service bloke. Ask them to inspect the transfer case fluid and linkage as part of your pre-trip service, not as an afterthought.

Diff locks, low range and the difference between the two

Worth clearing up here because the two get lumped together constantly. Low range changes your gearing. A diff lock (front, rear, or centre depending on your vehicle) stops a wheel with no traction spinning freely while the wheel with grip does nothing — it forces both wheels on an axle to turn at the same speed regardless of grip.

You can run low range without diff locks engaged, and on most moderate tracks that's exactly what you'll do. Diff locks come into play on the harder stuff — deep ruts, one wheel in the air, genuinely awkward terrain where open diffs will just send all your torque to the wheel spinning uselessly in the air. If your rig has a rear diff lock, low range plus the diff lock is usually the combination for serious low-traction terrain, not low range alone.

A track where you'll use every bit of it

If you want a proper introduction to what low range and diff locks are actually for, rather than a car park exercise, the Holland Track between Broomehill and Coolgardie will give it to you honestly, without the remoteness risk of somewhere like the Gunbarrel. It's got soft sandy sections, some rutted climbs, and enough variety in a single day that you'll shift between high and low range more times than you would in a month of coastal touring. Good practice ground before you take a fully loaded van rig somewhere with no phone signal and no easy exit.

I'll admit low range used to intimidate me — sounded like something for blokes in mud tyres and roll cages, not a retired footy-watching grey nomad towing a 21-footer. Turns out it's just a tool, and a fairly simple one once you've used it a dozen times. The trick isn't heroics. It's knowing it works before you need it, and using it before the wheels start spinning, not after.

— Trev Sanders, Grey Nomad Correspondent