4WD Servicing in Cairns

What a road service leaves out

A standard service covers the engine and the obvious fluids. On a four wheel drive that is maybe two thirds of what needs looking at, and the third that gets skipped is the expensive third.

Front and rear differentials, the transfer case and, on a manual, the gearbox all carry their own oil, on their own intervals, and none of them are part of a basic service. They are also the components that suffer most from what four wheel drives around here actually do.

Water in the diffs

If a vehicle goes through water at any depth, this is the first thing to check, and it is the single most common expensive failure we could prevent.

Differentials and transfer cases are vented, because the air inside them expands as they heat up. Drive a hot diff into cool water and the air inside contracts fast, and the vacuum draws water in through the breather. It happens in seconds and there is nothing you can do about it in the moment.

The oil comes out looking like coffee with milk in it. Water in a diff destroys bearings, and it does it over the following weeks rather than immediately, which is why the connection often gets missed. Someone crosses a creek in March and has a diff whine by June and thinks the two are unrelated.

If you have been through water, particularly around Gordonvale or anywhere the wet season puts water across a road, get the oils checked. It is a cheap check and the failure it prevents is not cheap. Extended breathers are worth fitting on any vehicle that does this regularly.

Salt, which is the slow one

The other thing that kills four wheel drives here is the beach, and vehicles working out of Portsmith or launching boats up the coast get the worst of it.

Salt attacks from underneath, and on a four wheel drive there is a great deal of underneath. Chassis rails, crossmembers, suspension mounting points, brake and fuel lines, exhaust hangers, and the fasteners on all of it. A bolt that has been in salt air for six years does not undo, it shears, and a simple job becomes a long one.

A proper underbody inspection is part of what we do, and where corrosion is starting we will tell you while it is still a wash-and-treat problem rather than a welding problem.

Driveline and the rest

Beyond the oils and the underbody:

• CV boots, which split and then let grit into the joint. A torn boot found early is a boot. Found late it is a CV.
• Universal joints and the tailshaft centre bearing, which announce themselves as a vibration at a particular speed.
• Wheel bearings, which take a hard time from water and from load.
• Hubs and locking mechanisms, where fitted.
• Suspension, bushes and shocks, which on a vehicle that carries weight or tows do not last the way a road car’s do. Those are covered on the suspension and steering page.

Before a trip

If you are heading somewhere where a breakdown is a genuine problem rather than an inconvenience, say so when you book. A pre-trip check is a different exercise from a service: it is looking for what will fail in the next few thousand kilometres rather than what is due, and it pays particular attention to belts, hoses, cooling, tyres including the spare, battery condition and anything already marginal.

Tell us where you are going and what you are towing. A run up the coast on bitumen and a week on unsealed roads carrying weight are not the same ask, and the check should not be the same either.