http://www.awdwiki.com

Nice one. That should while away a few hours  For a free country, it does seem pretty expensive these days.

Yeah, this is good reading. Nice one.

A very informative resource Alex - thank you.

Excellent source of information there Alex. Many thanks for that.  We Don't Care About Pot Holes !!

@Alex

Interesting, so if I am correct then MY09 models changed from the Haldex 3 up to the Haldex 4 generation with pro-active AWD.

Quote:

Freelander II 2006-2009 - Haldex generation III automatic all wheel drive. Normally a front wheel drive vehicle.
Freelander II 2009-... - Haldex generation IV pro-active automatic all wheel drive. Normally a front wheel drive vehicle.

Both Gen3 and Gen4 are proactive systems. In other words, all FL2s, from its production start at the end of 2006, have pro-active Haldex systems.

FL2 has (only) EDL (Electronic Differential Lock) included in its traction control.
You don't need to wait for the traction to come into play. Although viscous couplings you are thinking about - as on FL1s' cases - are quite quick.
But for traction control (and EDL) to kick-in, at least in FL2's case, is necessary to rev the engine past the 1800-2000 RPM mark.
The electronics are made this way because you need torque from the engine to give its best and not stall when the brakes are automatically applied (and 2000, as you know, is max torque point) and for a smooth, without jerks, braking of the spining wheel(s).

I've posted a small film on youtube for this to be seen.

See, and hear, at second 22, but more evidently at second 40.
Also this one:
And this one:

Thanks Alex, better understood now.

Thanks for the detailed explanations and the helpful videos Alex. Indeed that is the way the car behaves. When I tried my HSE i6 for the first time I got very disappointed. My previous car was a Jeep Cherokee 3.7 with central mechanical differential and low case gears. These kind of terrain (Cross Axles ) was a piece of cake for the Cherokee even in high case gears. With the Frelander2, I thought I got stuck. Took me some time to realize that if you press the gas pedal you can go further, presuming that you have space around you. Anyway my verdict is that freelander is way better on road than Cherokee and better off road when all wheels are in touch with the ground whatever that is (gravel, snow, mud etc). The only weak point is when one or more wheels are on air (the suspension travel is OK but limited compare with the Cherokee).
By the way which TR system is better with this kind of Cross Axles terrain?
In the petrol model in what RPM is the locking effect?

Thanks again!

Kostas

These cross axles situations are one of the toughest in off-road situations, like the guy also says on the site. See its videos section.

Even with cental mechanical differential, if you can't lock the center differential AND one of the two axle's differential (front or rear - rear in most cases) you won't move, if you start from standing still.

For example, on a three free differential car, like Defender, even if you lock the center differential making it act like a fixed 50/50 ratio transfer case, you won't move, starting from standing still, if both one front and one rear wheels are in the air. You must have and also lock one of the axles differentials too.

In other words, in cross axles situations, on a pure mechanical car, you must have two locked differentials in order to move. The center one and the rear one.

Like you've saw, the FL2 has handled it pretty well, considering that it was from standing still and uphill. Most cars with Electronic Differential Locks (EDLs) can't handle with the ABS the necessary braking force and torque transfer to move uphill a 2 tones car, in a cross-axle situation.
On its site, at videos section, the guy says: "If the vehicle was on a slope, it is doubtful EDL would make the vehicle move."
As you can see, the FL2 can handle this situation pretty well.

As for your question, the GGS mode is the most sensible one at wheel slip. So Grass, Gravel and Snow is best for cross axles situations.
Still, even though I made tests in all modes, in all my posted videos the car was in normal mode, the more "unfit" mode.

In gasoline version the RPM zone is around and above 2200-2400.

^^^^^^

I didn't realise how little I knew about the ins and outs of AWD/4WD. For a free country, it does seem pretty expensive these days.

Thanks once again for the info. Indeed to move up a 2 tones car is quite a job. In my opinion that is the difference of a capable 4x4 vehicle compared to the city SUV's.

Another thanks for a great link

Ok, I've been following this closely and have read the links…

People are saying you need 1800-2000rpm on board to get the system working in a cross axle situation. What I wonder is, is it related to engine speed, or wheel speed? Since it uses the ABS sensors, surely it is wheelspeed related? There may be an engine speed input into the logic too, but I'm not sure.

My reasoning is this - I guess it would depend on which terrain response mode you are in, but if you are in an auto and use CommandShift to lock it into second, or in a manual you simply select second - would the system respond quicker/better at lower revs?

The reason I pose this is: I have the 2010 TD4 auto and on a recent rock climbing trip I used the gravel setting and had the gearbox selecting 2nd gear and even with cross axles at times, there was very little flaring of revs or lack of progress seen in the videos - the locking seemed to happen very progressively and smoothly. The ABS came in very quickly to stop any wheelspin. I was really impressed how well it worked, even when I was on a steep incline, front wheels on pebbles and back on rock. I expected a lot of wheelspin and scrabbling but it was very well behaved… it gave a little spin, the abs groaned a bit and it just went up without any more fuss…

I guess some modes work better then others and there is an element of trial and error, but I kept up with a Defender and even had less wheelspin than him thanks to the electrics…

You could be right about the second gear and engine/wheel speeds.
In second gear the wheel rotational speed is greater with a lower engine speed.
And, if the wheel speed is taken into consideration by the traction control, the locking is at lower engine speeds BUT at the same wheel speed.
So you feel that the engine is not reving that much and have the impression that it's easier for the car, but the wheel spin/slip is the same as in first gear where the engine revs much more.

But as long as I know, and all instructors and books say the same thing, at crawl speeds, always select the lowest gear possible, even the reductor if it is present. You always have to keep the engine at the best RPM, close to max torque point.

But you raise a valid point and I know that I have now study material for the next outdoor escape.