I'm pretty inexperienced when it comes to 4 wheel drive so a few questions for the pros on the board:

I have about 4 different options 4hi (diff locked) 4hi (diff unlocked) 4lo (diff locked) 4lo (diff unlocked) and 2wd for the street.

OK, how do you know when to use which? I know that for really rough and slow you use 4lo but I'm not sure when you lock and unlock the differential.
Also, do you keep it in D unless it is steep and then step down to 3,2, or 1st gear?

For example, do you stay in 4hi and when you hit a deep mud area (for example) switch into 4lo and then back to 4hi when you clear it?

I read that on the beach, 4hi is good but locked or unlocked?

Thanks in advance for your help!

 

You would use (center) diff unlocked anytime you were on a high traction surface, like pavement, to allow the front and rear wheels to move freely. I would probably keep it unlocked until to got into terrain where you started to experience tire slip. With an open center diff and open axles front and rear, one spinning tire can leave you stuck. Locked center and you now have to have one front and one rear tire spin before you get stuck.
If you lock the center diff on high traction surfaces, you'll experience driveline binding as the front and rear tires follow different arcs while turning.

 

I usually keep the tranny in drive unless I'm going down a steep here where I want engine braking. The tranny does a pretty decent job of finding the right gear for going up steep hills.

 

I'm a beginner too, I'm just buying a Hilux Surf SSR-X. The main reason I need a 4x4 is to get me home down a very rough, rocky cliff track in S Wales.
The track's more or less bedrock in places, with loose scree in between, and quite steep in places. It's seen off many lesser 4x4s, such as Nissan X Trail, Freelander, because they don't have enough ground clearance. Even a Suzuki Grand Vitara tends to hit the rocks in places. I've been driving landrovers up and down the track for many years, but never quite understood much about diff locks, wheel locks etc, just always stuck them into 4 low and put the wheel diff locks on. The track's so steep you need plenty of engine braking and grip, especially in the wet.
Now I'm getting a nice comfy Hilux, I want to look after it, so could someone please advise me on when i should use the diff lock?

 

midnight surfer, since you have steep descents you might want to use the DSC- I haven't used it yet.

From what I gather, with the diff. UNlocked- the VSC and traction control is automatically on. So this will automatically not allow wheel skidding or "burning out" (meaning it won't allow you to floor it and light up all 4 wheels).

With the diff Locked- it turns off VSC and trac control. You will see the VSC off light up in your instrument pod. My thinking is that when the going gets rough, you lock the diff so you can keep the wheels turning and hunt for grip.

For example, I did a deep (for me anyway!) stream crossing and locked the diff. before going in. I thought that I would want the wheels to keep moving in case of slippage instead of the computer trying to brake/trac control the truck.
Did I do the right thing?

I believe the 4hi/unlocked is designed for on-road, snow, moderate stuff, etc. where maybe you are going at higher speeds... anyway, the manual says that you can drive in 4hi on any surface at any time at any speed. But you must drop below 60 mph to go from 2hi to 4hi and below around 20 mph to go from 4hi to 2hi... better double check your manual on exact speeds.

 

i have the big "TRANSFER GEAR SHIFTING INSTRUCTIONS" sticker plastered on my glove box. i think you can safely shift from 2hi to 4hi and back again at any sane highway speed, but it says to keep it under 5mph from going between 4hi and 4lo

 

i'm pretty sure that shifting between 2hi and 4hi should be done at speeds 40 MPH and below. As for the 4hi to 4lo, it needs to be 5mph or less (it's recommended that you stop). of course, it's probably always best to stop when shifting between 2hi/4hi/4lo.