The "lock" in "4WD LOCK" - what does it really mean?
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Four-wheel-drive was a niche feature back in the day.Unless you had a truck or an odd vehicle like an Eagle wagon, your vehicle was two-wheel-drive.With SUVs and crossovers replacing sedans as the default choice for everyday transportation, it's common for any given vehicle to have a quartet of driven wheels.That doesn't mean that all systems are equal.
Unless you have a fully automatic all-wheel-drive system, there will be at least two drive configurations you can choose to maximize your vehicle's capability in a given situation.If you drive an SUV with an off-road bent, like a Toyota Land Cruiser, you'll have more complicated choices, such as high range, locked or unlocked center differential.There are trucks and SUVs that offer all of the above, as well as all-wheel-drive vehicles.
If you want all-wheel-drive, it depends on the situation.Off-roading?The vehicle is 4WD.Is it possible to commute to work in three inches of sleet?In that case, it's the hot setup.
Four wheel traction meant four-wheel-drive in the early days of the SUV.A center differential that allows the front and rear tires to turn at different speeds is what most systems these days are.On dry pavement, four-wheel drive requires a slippery surface so that the front and rear ends can match speed without binding.
Most modern crossovers don't offer the option to disengage the system, they just work automatically when they detect slip.There is something you need to know even if you have that system.
Most of the time you can use the 4WD auto setting if you have a vehicle that offers two-wheel drive.It's fine for dry pavement, so the only advantage of running in 2WD is a fractional fuel economy benefit or saving wear on the front-drive system.Even if it starts raining, 4WD Auto is useful.
If you have a system that offers 4wd auto, 4WD High is useless.It's not doing anything for you on that snowy road because it just locks the front and rear end together.I would rather have the system sending power forward or back as needed most of the time.
A friend of mine used to own a late 70s Jeep Cherokee that was all-wheel-drive and the only time he needed to lock it was when he tried to drive through a pond.
Without an auto setting, 4WD High is what you'd use in a dirt road or snowy paved road.There are places where 4WD Low would help you out, like deep sand.Nowadays pickup trucks and SUVs with serious off-road pretensions are the only ones that have low range.A Toyota 4Runner would have it, but a Highlander wouldn't.
Let's say you're driving on the beach.We assume you let some air out of your tires because this isn't an off-road instructional.Good.What does the rocker switch do?There are four tires with a little "x" between the rear ones.The rear differential lock can be useful.
The rear diff lock connects the rear end to the front end.The opposite side keeps spinning if one side loses traction.If you're driving straight, it's a great feature.You don't want to use your diff lock on a corner because the whole point of a differential is to allow your car to make a smooth turn, with the outside tire turning faster than the inside.Your car won't want to turn if you lock them together.It will skid in protest when it does.If you bought a vehicle with a front differential lock, you probably know how to use it.
It's important to set your traction control before you go off-road.There are some lines on the button.The button is stability-control-defeat.
Keeping your tires from spinning is the goal of stability control.If you're on a rocky trail, stability control can mimic the benefits of locking differentials by grabbing the brakes at individual corners.We proved that with the car.