Off-roading Know-how – Tread Lightly

As responsible off-roaders we can, if we are conscientious, help minimise the loss of possible routes by driving only those lanes which do not damage easily. So if you learn of lanes which have either become badly rutted or washed away, give those a miss.

Another year could be drier and the lanes in question could be passable again.

So you have made up your group of three or four vehicles, sorted out sufficient and suitable recovery equipment, checked the maps, discussed your route and carried out a radio check on the CB. The lead vehicle arrives at the entrance to the first lane. Stop and think before driving along it. Has it been driven recently? Perhaps it’s too narrow. It could easily be well and truly overgrown.

If it’s not easily driveable, send a couple of passengers ahead with the portable CB. They can report on the conditions ahead.

If the track is too narrow, what’s the point in damaging the bodywork? If the ruts ahead are too deep, what’s the point in damaging the track further and spending several wasted hours in trying to conquer it?

Perhaps the lane in question is across a moorland area. Does the defined track ahead look boggy? If so, walk ahead and possibly think twice. You might be glad you did!

No route anywhere will ever be the same along its entire length, especially in mountainous and moorland areas, so always think ahead. Remember the saying: tread lightly on public and private ground.

Avoid damage to the countryside by irresponsible driving. Leave all gates as you find them. Don’t always assume that gates should be closed across farmland dividing fields. It is possible that the farmer may well have left that gate open for a reason. But if in doubt, close it. Use your common sense.

When passing or overtaking other users, be courteous at all times and thank them if they have stood aside to let you pass. If you have done your homework correctly, you have as much right as they have to be using the route. Stop for those approaching on bicycle, trial bike and horse, to let them pass. For horses, switch your engine off.

Think of yourself as a visitor to the countryside and respect the environment. Drive slowly: three to four miles per hour is about right.

Enjoy the countryside. Don’t wreck it by driving too fast. Remember you can be spotted a long way off by other users and by local people, especially if you are driving recklessly.

It pays to spread out with a couple of hundred metres between each vehicle, which makes passing vehicles coming the opposite direction so much easier.

This is where the CB proves to be most useful. The lead vehicle can advise those behind as to oncoming traffic.

Remember, to make sure that each vehicle keeps sight of the one following it, so as not to lose them en route. Convoy rules must always apply.

Four-wheel drive systems

Before driving off-road, let’s take a look at the various four-wheel drive systems that Land Rover use on Series I, II & III, 90 and 110, Discovery and Classic Range Rover.

Permanent four-wheel drive

All current Land Rover products have permanent four-wheel drive transmission (known also as full-time). Range Rover was the founder vehicle with this system way back in 1970.

Land Rover first used it in 1980 with the launch of the Stage One V8 and three years later it became the standard transmission system for the ‘new’ 110, followed a year later by the 90. Owners of 101s will be quick to point out that these vehicles also used this system for the few years that they were produced for military orders.

The system incorporates a centre differential to prevent ‘transmission wind-up’. This is the term given when any four-wheel drive vehicle, having a fully locked up centre transfer case between the front and rear propshafts, winds up when the vehicle is driven around a corner on tarmac or concrete. This occurs when the road wheels on the outside of the bend have to travel a lot further than the wheels on the inside of the bend.

Either pulling the button upon pre-1982 Range rovers should lock this centre differential, or pushing the low range lever over to the left on later models; likewise on Land Rover 90, 110,130 and Discovery, when traction is likely to be lost at one or more wheels.

Range Rovers made after 1988, or thereabouts, is the exception to the rule as they are fitted with a user-friendly automatic ‘viscous control unit’ (VCU). In conditions such as ice, snow, and mud or on other surfaces requiring maximum traction, uncontrolled spinning of wheels will be limited by the viscous control unit, which is combined within the third centre differential.

The action of the VCU is automatic and its effect is to distribute the driving torque from the transfer box to the axles in proportion to the available adhesion. In simple terms, when the VCU sense one propshaft revolving at a different speed to the other, the unit ‘locks up’ to ensure that a proportion of drive goes to the axle with the weight on it, for example, when climbing or descending hills.

On vehicles fitted with a centre diff lock, do not attempt to either engage or disengage the centre differential when:

a)Any road wheels are spinning on slippery ground, or b)When turning a tight corner.

It can, however, be either engaged or disengaged at any speed, in any gear, without the use of the clutch, providing you are steering straight ahead. If you have inadvertently driven into a muddy area, having forgotten to engage the diff lock, back off the throttle to stop any wheels that may be spinning, then engage.

It is very important that you disengage the centre differential before you arrive back onto tarmac or concrete. If you accidentally end up with the centre diff warning light still on when back on a hard surface, you must stop and reverse back in a straight line far enough for the ‘wind up’ to clear. The extinguishing of the warning light will tell you when the centre diff is ‘unlocked’.

Alternatively, if you have a wet grass verge right next to you, drive with one wheel on it and blip the throttle to cause a spin-out on one corner. Another way to clear the wind-up in a confined space is to jack up one end of the front axle just enough to take a road wheel off the ground. If you persist in driving on hard tractive surfaces with the centre diff lock engaged, you could break something very quickly indeed. You have been warned!

One of the best assets of a vehicle with permanent four-wheel drive is that you can manoeuvre heavy trailers and caravans slowly in low ratio on a level hard surface providing you do not engage the centre diff.

Selectable four-wheel drive

All Series I, II and III Land Rovers, and the majority of other makes of off-road vehicles have a selectable four-wheel drive system (known also as part-time). This is where normal on-road driving is in rear-wheel drive only, the front propshaft being disengaged from the transfer case.

The ironic thing is that, unless free wheel hubs (FWHs) are either manually or automatically disengaged when fitted, the front propshaft is still being turned by the road wheels while on the move.

If your Series I, II or III hasn’t got a set of manually operated free wheel hubs fitted, then buy a set. What’s the point of having all the components forward of the transfer case merrily spinning around wearing out, and using unnecessary fuel?

Remember, though, to engage them once a week for a few miles so as to engage the front drive shafts. This lubricates the top pivot inside the swivel housings by throwing up oil from the universal joints inside. If this is not done regularly, the pivots and bushes will start seizing up and you may wonder why your steering goes stiff.

You must engage the FWHs before going off-road because, if you forget, when dropping into low ratio all the torque goes straight to the back axle only and this has been known to break half shafts.

However, driving carefully while manoeuvring trailers on a hard level surface with the FWHs in the 4×2 ‘free’ position you can reverse the trailer in a low ratio more slowly without the fear of getting ‘wind-up’.

It is possible, though highly unlikely, that you may come across an early Land Rover fitted with Fairey automatic FWHs. Fine for on-road use, but dodgy for off-road use. The reason being, when descending a very steep hill in an overrun condition, they could disengage!

Finally, on the subject of selectable (part-time) transmission every Series I’s had, in fact, permanent four-wheel driving utilising an overrun dog clutch system on the front of the transfer case to drive the front propshaft. You can always tell one of these vehicles, as it is the model with the chain coming up through the hole in the floor. The idea is to pull, or lift, the chain to engage four-wheel drive when reversing in muddy conditions!

Engaging low ratio

Just before driving into an off-road area, make sure you engage, if required, low ratio. Your transfer case gives you a completely extra set of lower gear ratios to enable you to tackle demanding off-road conditions as well as ensuring you keep your speed down to a minimum.

On all permanent four-wheel drive 90s, 110s, Classic Range Rovers and Discoverys and Stage One V8 Land Rovers, the selection of low ratio is done by moving forward the short stubby transfer case lever. Do this only while the vehicle is stationary, preferably with your foot on the clutch.
If you find it difficult to either get from high ratio into the mid-neutral position or indeed into low ratio, simply – while on level ground – place your foot lightly on the footbrake, take off the handbrake, depress the clutch, put the main gearbox into first. With a light hand pressure on the transfer lever, ‘feel’ it come out of high ratio, through neutral, and with a slight ‘clonk’ into low ratio as you play on the clutch.

With practice, you will achieve this operation very easily. More often than not, the reason why it is difficult to engage low ratio is because the vehicle is either very new, or that low ratio is rarely used.

If your first manoeuvre is descending a hill or down a bank, keep your hand on the transfer lever with the intention of ensuring that the lever doesn’t fall back into neutral position. Ideally, make sure you engage low ratio and diff lock several vehicle lengths before ‘going over the edge’.

On all Series I, II and III Land Rovers you engage low ratio only while in the stationary position by pulling the tail transfer lever with the red knob back towards you through neutral into low. It should never be difficult to engage, but again be fully happy that it stays engaged as you move off ‘over the edge’. Remember to engage the manual free wheel hubs first, if fitted.

Once you have engaged low ratio, providing you are proceeding ahead on level ground or starting a climb, by all means move off in second gear. After all, you are in low ratio!

If your vehicle is fitted with a Superwinch (Fairey) overdrive unit, be sure not to use it in low ratio – you will simply wear it out. You should in fact, only be using it in third and fourth gears – high ratio. In saying that, if the need arises, and the only way out is to reverse in the mud or up a slope, engaging overdrive while in reverse might just get you out of a predicament by causing less spinning of the wheels. Remember to disengage it as soon as you are out.


Re-engaging high ratio

As regards permanent four-wheel drive vehicles, although I prefer to stop before bringing the transfer lever back into high ratio, you may do it carefully on the move.

Imagine the situation. You are coming off the muddy track up onto a tarmac road and you daren’t stop for fear of losing momentum and therefore getting stuck.

While moving along in low ratio, no doubt in either first or second gear, simply place your hand on the transfer lever with a very slight pressure back towards you into neutral. At the appropriate moment come off the throttle and double declutch by pressing down on the clutch once as you bring the transfer lever into neutral, letting the clutch out momentarily. Then, while depressing the clutch for the second time, bring the lever back into high ratio before letting the clutch off for the last time. Ensure that your engine speed is reduced as you continue on in high ratio and that your centre diff lock clears also just prior to reaching the hard surface if turning one way or another.

Sounds complicated, but not really in practice. Try it several times while on the level, with the front wheels straight ahead. Ultimately you will master this with no more than a slight ‘clonk’ coming from the transfer case. I prefer to bring the vehicle to rest before changing back into high ratio as in the case of engaging low, but of course this is not always possible.

On part-time transmission Land Rovers, very carefully push the transfer lever from the low ratio position through neutral into high, double de-clutching between both movements allowing the engine revs to drop off.

Using high ratio four-wheel drive

There are occasions when you might decide to use high ratio four-wheel drive apart from when driving in snow and icy conditions. I suggest, however, that you only use high ratio off-road when conditions allow, for example, on easygoing level slippery tracks with few undulations in the surface. You have to remember that, when travelling along tracks, you have very little engine braking to slow you down should you come across an obstacle such as a washed-out hole. Remember also that, when driving in high ratio, you could be travelling a shade too fast.

However, if the ground conditions allow and you feel happier to use high ratio, you will of course be using less fuel. Remember to engage the centre diff lock on permanently-driven vehicles if appropriate, disengaging just before turning onto tarmac roads, or drier, harder ground.

On part-time transmission Land Rovers, simply engage high ratio four-wheel drive by pushing the spring loaded lever with the yellow knob down firmly.

When coming back onto a hard surface, you must stop, and disengage four-wheel drive low ratio by pulling the low ratio lever with the red knob back towards you, which allows the spring loaded yellow knob to pop back upwards. Then push the low ratio lever back forward again to give two-wheel drive high ratio.

Automatic Models

You can change ratio down from high to low, or up from low to high, while the vehicle is moving.

Reduce or accelerate the speed as applicable to about five miles per hour. At this speed, take your foot off the accelerator, move the auto shift lever into neutral, then move the transfer lever quickly into the required high or low position. Finally select ‘drive’ on the auto shift lever.

Electronic traction control

Certain models of the Classic Range Rover are fitted with an ‘anti-lock braking system’ (ABS), which incorporates an ‘electronic traction control’ system (ETC).

The ‘electronic control unit’ (ECU) which controls both systems incorporates a monitoring system which checks that all electrical components are in working order, not only before each journey but also at frequent intervals while the ignition is switched on. Well, so I am told!

The purpose of the ETC is to aid traction when one rear wheel spins while the other still has good grip; for example, if one side of the vehicle is on mud or ice and the other on hard ground or tarmac. ETC is an extension to the ABS, there being a modified electronic control unit with extra software and outputs, an add-on valve block to provide pressure to the rear brakes, and an information light.

The system works by applying the brake to a spinning rear wheel to transfer torque to the other side of the axle. A normal open differential is a torque balance, so if one rear wheel cannot get traction due to mud or ice or because it is off the ground (through being cross-axled) when the other rear wheel gets the same level or torque (very little). If the brake is used to similar torque resistance for the spinning wheel, then this torque is sent to the other rear wheel with the grip, thus providing traction.

The ETC system has an information light to let the driver know when it is active. This comes on all the time that the ETC unit is active and for a minimum of two seconds. In the unlikely event that the ETC is used too long continuously (over a minute), then the unit shuts down to allow cooling and the ETC light is flashed. If there is a fault with the ETC system then the ETC light comes on permanently. Magic stuff, this new technology!

Safety First

Before actually driving off into the rough, let’s consider a few important points to ensure not only your safety and the safety of your passengers but also to increase the reliability of your vehicle.

Belt up: whenever driving a legally driveable unsurfaced byway, just as in the case of a fully maintained highway, you must by law wear safety belts as fitted to your vehicle.

Even when driving off-road over private ground it makes sense to wear them. Especially the passengers, who don’t have a steering wheel to hold onto to give them a sense of security. If may be OK for you, the driver, to drop the front wheels into a hole. You might be expecting it to happen, but spare a though for your front seat passengers.

With inertia belts, some may be concerned that the diagonal strap self tightens as you bounce about a bit when climbing a hill, making it difficult to lean forward to look over the bonnet to see the way ahead. No problem. Having put the safety belt on a given a small amount of slack to make the diagonal comfortable to wear, secure a clothes peg above your shoulder just under where the belt goes through the anchorage point. That will stop it from tightening up.

Protect your thumbs: when driving off-road there is always a risk of the steering wheel kicking back if one of the front wheels snags on a rock, or a tree stump. Please keep your thumbs out of the spoke area so they cannot get trapped by a spinning steering wheel should it fly out of your hands. When holding the steering wheel in the ‘ten to two’ position, run your thumbs along the front surface of the rim.

Do not ride the clutch: It’s so easy isn’t it, to rest your left foot on the clutch most of the time? Well don’t, because if you do, every time you hit a bump you will cause the clutch to spin which will obviously wear it out very soon.

Apart from that, in a panic situation descending a hill, it’s too easy to accidentally use your clutch and freewheel to the bottom of the hill – with alarming results!

The only time you need to use the clutch is when either moving off, changing gear of coming to a halt. When not using the clutch, keep you left foot flat on the floor.

Footbrake: when ground conditions are wet and muddy, only use the footbrake when coming to a halt, say on the crest of a hill while changing from climbing gear to a descending gear, stopping all four wheels from spinning. Or when changing from a climbing gear to a reverse gear on a failed hill climb, or drying the brakes out after wading or coming to a halt.

Well, that’s the theory, but in practice, you can use the footbrake with great care by feathering the brakes when tackling a dry rocky descent should your petrol-engined vehicle start to run away with you. If the surface is loose or slippery in any way do not even consider using the footbrake – don’t say you have not been warned.

Diesel-engined vehicles usually have enough engine braking so as not to need to use the footbrake.

Classic Range Rovers fitted with ABS brakes are again an exception to the rule. I will cover this in detail under ‘descending’.

Throttle: as in the case of the clutch and footbrake, always use the pedals extremely sensitively avoiding abrupt movement which can cause the vehicle to lurch. Always drive off slowly when in mud or difficult terrain, so as not to spin the wheels.

If accelerating, ease the revs up slowly trying to keep the wheels running with the ground. Undue wheel spinning will only cause you to slip and slide about, filling the tyre treads with mud.

For slowing up, rely where possible on deceleration through engine braking, by easing your right foot back off the acceleration pedal. Driving on the throttle is always the best way to control the vehicle.

Handbrake: when driving through thick mud and wading deep water, don’t expect the handbrake to work too well. If you need to stop on the brow of a hill for instance, switch the engine off and leave the vehicle in either first or reverse, depending on how it is lying. Do this in addition to the handbrake. Never stop the vehicle on the handbrake.

Land Rover products have a transmission brake; if used abruptly, you could easily damage the drive train through undue strain. If you did need an emergency brake, say if you footbrake failed, simply keep your thumb on the handbrake release button and ease up slowly. Don’t release the button until you have stopped.

Wading Plugs: fit these before going off-roading. There’s nothing worse than lying under a muddy vehicle in thick mud and pouring rain trying to fit them.

Roof rack loads: if you have a roof rack fitted, make sure any items aloft are well secured. Remember that heavy items up there will raise your centre of gravity.

Survey on foot: if the route ahead looks particularly difficult, remember to walk the immediate route ahead. This is a wise precaution, as it will minimise the risk of getting caught out while negotiating an unnoticed hazard.

Your survey will help you decide which gear to use. Picking a higher gear might induce you to drive too fast, or stall the engine. It is important to understand that you should not attempt to change gear halfway through driving an obstacle other than cresting a hill where you change from a higher climbing gear to a lower descending gear.

The reason for this insistence to stay in the same gear to complete the obstacle in front is simply this. If you try and change gear, you probably reduce the momentum when climbing, or run a real risk of missing a gear and being left in neutral when descending.

In the next part I shall continue with the first lesson in driving rough tracks.

LESSONS IN OFF-ROADING

  • Know your four-wheel drive system
  • Familiarise yourself with the controls
  • Driving rough tracks
  • Ascending, and deleting with defaults
  • Descending – safely !
  • Traversing side slopes – with care !
  • Crossing ditches and driving gullies
  • Driving across soft ground
  • Wading – everyones favourite pastime !
  • Checking the vehicle over afterwards

Telephone: 01363 82666

Fax: 01363 82782

Email:sales@goodwinch.com

Goodwinch Ltd, David Bowyer's Off Road Centre, East Foldhay, Zeal Monachorum, Crediton, Devon, England, EX17 6DH

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