When is it exactly right to engage 4WD?

[Billiebob]

doesn't matter off or on road.
seriously doubt you'll find ANY manufactor that would recommend going over 20mph in 4lo, you'd be spinning your t-case so fast it would literally grenade.
60 mph is even pushing it for almost any t-case in 4 hi as well

and yet, 30 years later, 500K kms on my YJ lots of it in 4L,,, sold it with the original transfer case.
My TJR never hits 30mph in 4L.... lol but that might be because of the 4.10s and 4:1 transfer case.
The YJ was 3.07s and 2.72? transfer case ratios.

You guys are listening to old wives tales.

But then I've only had Jeeps and Fords, I cannot vouch for the durability of other makes.

 

[LostInThought]

Hi, I'm new to overlanding, and off-roading.

I've read that you should never engage 4WD unless you're in a low traction situation, otherwise you'll mess up a lot of things.

So is there an exact minimum on how, for example, wet the road has to be?

You just divide the cube root of velocity by the friction coefficient...

Nah, I'm just kidding you.

The problem is that when turning, the vehicle's wheels need to turn at different speeds. Not a problem if you're in 2wd - the front wheels are spinning freely and the unlocked rear diff takes care of the rear wheels. Also not a problem if the surface allows the tires to slip/slide a little (dirt, gravel, sand, snow, ice, mud, etc). BUT because pavement is a high traction surface, pavement and 4wd don't mix, not even wet pavement. Wait for a poor traction surface (again dirt, gravel, sand, snow, ice, mud, etc).

**IF** you accidentally forget to drop out of 4wd as you come back onto pavement, you may encounter a situation when turning, in which the vehicle suddenly feels like the brakes are on. STOP. Forcing the vehicle in this state will typically twist axles or drive shafts and may cause one to fail (usually, they are designed to break first to protect the more expensive diffs & transfer case in this situation). Drop back out of 4wd. If the vehicle won't disengage 4wd, you may need to either back up or turn the wheels the other direction or drop into neutral and turn the wheels until you can disengage 4wd. Check your owners manual for tips on disengaging.

The one warning I'd offer is that 4wd on ice drives differently than you're probably accustomed to and isn't always "better". Try it out on an icy parking lot where you have room to make a few mistakes.

 

[konstantinejaquavis]

Hi, I'm new to overlanding, and off-roading.

I've read that you should never engage 4WD unless you're in a low traction situation, otherwise you'll mess up a lot of things.
Speed Test
So is there an exact minimum on how, for example, wet the road has to be?

These have rear and central locking but I can only engage lock system in Low range 4x4

 

[H2OBound]

I used to have the “use it only when you think you need it” perspective, but after watching this I changed my mind.

 

[leeloo]

just read the bloody book of your vehicle, many 4wd systems out there and is too long to describe them all.
Some have very specific recommendations, like the maximum speed, traction conditions and so on,
On the vehicle I had before it was stated for example that I should engage the 4wd at least every 3 months or 3000 km, even if it is for a short while. No answer to fit all situation, so if you don't have your owner's manual just google it, you will find it and lose 10 min to read the part about the 4x4 system , might save you some expensive repair.
Me personally I think the safest and easiest to use would be a permanent 4x4 with locking center diff and maybe rear, like the ones found in a Land rover or Land cruiser.
The beauty of it is that you have some kind of 4x4 traction at any speed, and that increases safety in other conditions, not only at off road.