Extended height mode

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Originally Posted by CaverD3

I have had all four wheels spinning on wet grass and clay and it did not go into extended mode so I suspect it will do so only if hung up.

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You were probably still inching forward (or backward!), so it wouldn't trigger.

How would it know? If it was efffectively stationary on flat ground (which I have done) it would not pick up the inertia to tell if it was moving and the wheel speed would be irrelevent. :confused:

It cannot sense that it is "hung up" directly - there are no sensors/cameras that inform it of an obstacle in contact with the underbody. If you trigger a lowering of the vehicle and the lowering is impeded, it can sense that by noting the spring pressures and the height sensor readings. As you didn't trigger a lowering (I presume?), the car could only have raised itself by comparing the relative wheel speeds and the input data from the yaw and accelerometer sensors and concluding that you were stuck.

Cheers,

Gordon

All four wheels spinning on my D4 caused it to go to extended height. Vehicle had no forward movement and was on sand, but had not dug down.
Have also forced the lift the way Gordon showed me....to impress the family.
Smart bit of kit....apart from not liking steep sand dunes in high range.
Brett....

Yes, I suspect negative air pressure in the bags combined with downward movement detected by the suspension sensor.
Mine has gone into extended without being hung up but under extreme articulation.
Could go into extended mode differently in different TR settings with different perameters. :idea:

Very clever programing though and they improved it with the D4! :D

I have some video of a D3 on AT's and a D4 on road tyres, both in rock-crawl on the same obstacle - a noticeable difference viewing from outside the car, even though from the inside they both felt just as competent. I'll post it up on my YouTube channel.

Cheers,

Gordon

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Originally Posted by gghaggis

I'm pretty sure I've posted a few dozen times on this, but for the benefit of new members having trouble with the search function ...........

1. The car will enable extended mode if all 4 wheels are spinning and there is no forward motion, OR if it senses an obstruction when lowering. Extended is approx 35 ~ 40mm above whatever height you happen to be in.

2. ONLY when in extended, emergency (or super-extended) can be selected by the driver. With the vehicle stationary and motor running, hold down the brake pedal and select-and-hold the "up" position on the EAS switch until the car chimes. It will then raise a further 30mm or so (it is dependent on the individual car's calibration, amongst other things).

3. In either extended or emergency height, the car will lower back to the original height setting as soon as you exceed 8kph, travel for more than 45s continuously, restart the car or change TR setting.

If you need to raise the car to it's MAXIMUM height, without waiting for it to select extended height automatically, then follow this procedure with the car stationary, engine running, in low range and in Park:

1. Place the car in whatever TR program required (normally rock-crawl).
2. Raise the car to offroad if it has not already automatically raised (as it should when you select a TR program).
3. Use the LR jack and position it under the driver's jack location under the chassis rail. Wind up the jack until it has just taken the weight of the car (you can do this by hand).
4. Get into the car, close the driver's door and select "normal" height with the EAS switch. Don't apply the footbrake!
5. The car will attempt to lower, sense the obstruction and then raise 35mm above offroad.
6. Now apply the footbrake, and hold the EAS switch in the "up" position until the car chimes and raises a further 30mm or so.
7. Remove the jack from under the car!

Not every step is required in some situations, but if you follow all 7, you're guaranteed to get the car to raise. Note that the jack should be on firm ground, or you should have a footplate for it, to prevent it being pushed into the ground by the car (and hence it will not raise).

As rmp has pointed out, be careful with the throttle and full turning lock when at these heights. You almost NEVER need a heavy throttle when in rock-crawl, so don't be tempted to try it. The CV's are very strong, but any vehicle on full lock and at extreme wheel articulation will stress the CV.

Cheers,

Gordon

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Thanks Gordon.

I've never measured the heights and was unaware that there were two stages to extended mode. I thought once the car bottomed out that it returned to the offroad height and then notified you that extended was 'available'.

I guess offroad on uneven ground it would be hard to tell that the D4 is up another 35 - 40mm, even if you were outside the car.

Thanks for the info.

Cheers,

Kev.

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Originally Posted by gghaggis

I have some video of a D3 on AT's and a D4 on road tyres, both in rock-crawl on the same obstacle - a noticeable difference viewing from outside the car, even though from the inside they both felt just as competent. I'll post it up on my YouTube channel.

Cheers,

Gordon

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Thanks Gordon. :D

Link?

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Originally Posted by rmp

It is the case with all CVs and driveline components irrespective of manufacturer.

If you want to snap something this is how - find a hill with good traction, select low range reverse, full steering lock, angle for maximum suspension flex and then stab the throttle. Bang will result in pretty much any car...

...By the way if you do snap a CV in a Disco put it into Rock Crawl so it can still move. .

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+1...

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Originally Posted by rmp

Unlike previous Landies, the drivelines in D3/D4/RRS is strong and not prone to breaking. The cars have other bush problems, but strength of transmission is not one of them! However, strength does not mean they are tolerant of abuse, as I said I've seen them break.

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Ish... I've seen them break too.

IMO - One of the things which makes the T5 platform more tollerant is the auto gearbox. An auto means that the drivetrain, splines, etc... are more constantly loaded, so less likely to be 'shock' loaded.

Previously, most people would drive manuals. Without training, I find that most people tend to use the clutch more as an 'on/off' switch. 'Shock' loads are more likely to snap drive train components.

M

You may be right... I was sitting there spinning the wheels and found we weren't going anywhere so I tried reverse straight away and got out, it wasn't until later I remembered this option to raise car, but I had no warning as to how, so I wasn't sure how it was to work. We were in the middle of no where and no ph service so it took me by surpise that a D4 could get stuck in something that didn't look hard to drive through, must have been the stock tires lol