The following information is common to all types of 4WD’s. Each make and model will vary slightly, but grasp these basics and you are well on your way.
Differences Between 4WD and 2WD
The first difference you will notice is that the 4WD has far greater ground clearance than a 2WD.
Some 4WD’s have what are called free wheeling hubs fitted to the centre of the front wheels. These hubs can be either manual, where there is a knob to be turned, automatic, where once in 4WD the hubs lock automatically or a combination of both. The idea of free wheeling hubs is to disconnect the front diff and axles from the wheel, so when traveling on highway, the vehicle doesn’t have to use extra power turning these when they are not wanted.
On the inside of the vehicle you will notice either an extra gear lever or dial on the dash which allows you to shift the vehicle into high or low range 4WD. As a general rule, for moderate inclines, slippery or sandy situations, use 4WD high range. For very deep water crossings, steep or rocky ground use 4WD low range. If you are not sure about this read your owners manual or join a club.
Servicing on a 4WD is normally at more frequent intervals, especially if you are involved in real 4WD work with lots of low range, river crossings or particularly dusty conditions.
Hand Position on Steering Wheel
When driving off road, it is important not to place your thumbs on the inside of the steering wheel. When driving over any large ruts or potholes, the wheel could suddenly turn. This may result in the thumb being bruised or even dislocated if it is left inside the rim. Remembering to leave your thumbs on the outside of the steering wheel is a very easy skill to acquire and should become second nature to you. With power steering fitted to most 4x4′s these days, this technique is not as critical as the power steering unit dampens out sudden steering wheel movements as well as steering stabilizers. Owners of non-power steering vehicles will have undoubtedly experienced at some time the force at which the steering wheel turns when hitting an obstruction.
Lowest Point
It is important to know the position of your front and rear differentials as they are usually the lowest point of your vehicle. Similarly, any other low ground clearance points should be noted e.g. exhaust, spare tyre etc. When a large rock or other obstacle is on a track that you must drive over, you should ensure you avoid driving directly over it with the lowest ground clearance point of your vehicle.
Braking
When using the vehicle’s brakes hard, your vehicle’s front suspension compresses and you ‘use up’ most of its suspension travel. When braking heavily to avoid an obstacle e.g. pot hole or rut, and you cannot stop in time, release the brake pedal just prior to hitting the obstacle. This will allow the front suspension to return to its normal height and give more suspension travel when hitting the obstacle.
Tip:
When fitting new brake pads, don’t buy the cheap ones, you’ll find a lot of brake fade when descending long downhill stretches and water logging when doing river crossings.
Vehicle Limitations
Remember, a four wheel drive cannot be treated like a normal car when cornering. The 4WD will roll over much easier than a car while cornering, due to the higher center of gravity. This applies to gravel and paved roads equally. Although a four wheel drive vehicle generally has better traction on gravel than a car, when safe cornering speeds are exceeded the four wheel drive will tend to roll earlier than a car.
