Keeping Your 4WD in Good Nick — Maintenance + Modifications

A 4WD costs $50,000-100,000+. The maintenance schedule decides whether it lasts 250,000km or 600,000km. Off-road driving — the dust, water crossings, mud, towing — demands more from filters + fluids + brakes + driveline than highway commuting ever does.

Here's the practical guide to keeping your 4WD in good nick — preventative maintenance, the right driving choices, post-trip inspection, and the modifications worth fitting.

Photo by Stephen Mabbs on Unsplash

• Stick to manufacturer service intervals — typically 10,000-15,000km or 6 months
• Reduce intervals for off-road use — half the recommended km if you're regularly bush-driving (more contamination)
• Engine oil + filter — the most important. Cheap insurance against expensive engine damage
• Don't forget gearbox + differential oils — often overlooked. Water crossings contaminate driveline lubricants. Replace per schedule
• Coolant — replace at recommended intervals; maintain correct strength for freezing/boiling protection
• Brake fluid — heavy use exposes any moisture in old fluid (spongy pedal, possible brake loss). Flush every 2 years minimum
• Brake pads + shoes — check at every service. Replace BEFORE they go to the rivet
• Air filter — clogs faster on dusty bush roads. Visually check; replace when grey/dark
• Fuel filter — extra critical for diesels. Carry a spare on remote trips

• Extended diff + gearbox breathers — fits a hose so the breather sits high in the engine bay (not at the diff/gearbox where water can be sucked in). Game-changer for water crossings
• Extended fuel tank breather — same principle for fuel tank
• Snorkel — raises the air intake above water level. Mandatory for serious water crossing
• WALK the crossing first if at all unsure of depth — your boots tell you what the wheels can't see
• Drive at a steady walking pace creating a small bow wave — that wave keeps water away from the engine bay
• After every crossing: check for water in the airbox, wheel bearings, brake drums. Worst case = $$$ damage; lucky case = water expelled by next 50km of driving

Photo: Zac Edmonds / Unsplash

• Bullbar — animal strikes are the #1 outback breakdown cause. Steel = strongest; alloy = lighter compromise; poly = city use only. Worth it if you regularly drive in roo country at dawn/dusk
• Underbody protection plates — sump guard, gearbox guard, transfer case guard. Cheap insurance against rock damage
• Side rails / rock sliders — protect sills + body from rock damage on rocky tracks
• Quality recovery points — front + rear, rated. NEVER use the tow ball as a recovery point (kills people regularly)
• Suspension upgrade — heavier springs + better dampers handle the touring weight + rough roads
• All-terrain tyres — bridge between highway + mud-terrain. Best all-rounder for most touring 4WDs
• Tyre Pressure Monitor System (TPMS) — alerts you to slow leaks before they become blowouts
• Dual battery system — for fridges, lights, accessories. See our 12V fridge guide

How you drive matters as much as what you drive. The "stump-jumping, full-noise" approach destroys 4WDs faster than rough country itself.

• Appropriate gear selection — low-range L1 or L2 for technical descents; smooth power application
• Suitable line of travel — read the track ahead, plan your wheels, avoid the worst ruts
• Sensitive throttle — jerky inputs damage the driveline. Smooth + progressive
• Tyre pressure for terrain — gravel: 30 PSI; sand: 18-22 PSI; rock: 25-30; highway: 40+. CARRY a compressor + gauge
• Avoid deep bog holes — take the bypass; explore in drier conditions
• Limit braking in mud + sand — relies on engine braking instead
• Wash off mud early — corrosive + abrasive if left

Photo: Iszac Bale / Unsplash

• Salt spray attacks the undercarriage + bodywork fast
• Wash thoroughly + as soon as possible — pressure wash undercarriage especially
• Regular beach goers apply protective coatings (Lanotec, fish oil) to chassis + driveline
• Some fit electronic anti-corrosion devices — debated effectiveness
• Don't park on the beach overnight — saltwater fog is brutal
• Lower tyre pressure for sand driving (18-20 PSI) — improves flotation, reduces engine load

Apart from being illegal to exceed your true load rating, overloading puts enormous strain on the drivetrain + reveals weaknesses fast.

• Visit a public weighbridge with full touring kit + caravan/trailer if towing
• Stay UNDER: GVM (vehicle), GTM (trailer), GCM (combined). See our towing guide
• Carefully weigh up every item packed — what's NEEDED vs nice-to-have
• Heavy items low + central for stability
• GVM upgrades available for serious touring rigs (Cruzers, Patrols) — engineered upgrade kits raise legal max load

• Thorough wash — pressure wash undercarriage, body, wheels. Get all mud + salt off within days
• Vacuum interior — sand + dust everywhere
• Inspect for damage — look under, around tyres, behind splash guards
• Check fluids — diff oil should be clean amber, not milky white (= water in the diff = action needed)
• Address small repairs immediately — small problems become big problems if left
• Re-pack the recovery kit — replace anything used, check straps for damage

Modern 4WDs are remarkably capable + reliable — IF maintained. The basic schedule + post-trip routine costs a few hours + a few hundred dollars per year. Skipped, the cost compounds fast — sticky differentials, worn brakes, rusted bodywork, premature engine wear.

The mods worth fitting depend on your use. City + occasional trips: minimal. Regular touring: bullbar + protection plates + suspension upgrade. Serious remote: extended breathers + dual battery + recovery gear. Match the kit to the country.