Thread: Climbing dunes in a D4 - engine cutting revs

Such an aggressive cutting of engine revs doesn't seem like any instances of DSC application I've experienced or heard of.
But others may know more.

Did you notice a light something like this photo flashing up on the dash?

This is the DSC actually doing something.

Was there any holes in the sand causing side-to-side rocking or was it pretty much straight up?
Is it at all possible you had switched between TR modes or turned engine off and then forgotten to turn off DSC again?
(I'm not being smart, it's just something that's happened to me).

Also, 3800 revs is pretty high and you mention being in high range.
Did this go on for long?
Could it have been a thermal issue, perhaps transmission?
Any other lights/symbols on the dash?

For this type of work I always use low range, more sympathetic to the drive train.

Cheers,
Scott

Yep, i have experienced something similar on Fraser island. Not as drastic but there was a definite drop in power. Only seems to happen in high range and not low range in my experience. I thought it was to do with the trailer attached at the time but couldnt pin point it.

I certainly wasn't that high in the rev range but the throttle definitely didn't respond to input when asked and stopped it prematurely. Low range in sand is more reliable in my experience on the trips thus far as Scott suggests

Originally Posted by LRD414

Did you notice a light something like this photo flashing up on the dash?

This is the DSC actually doing something.

Not that i recall - and i was keeping an eye on the tacho.

Originally Posted by LRD414

Was there any holes in the sand causing side-to-side rocking or was it pretty much straight up?
Is it at all possible you had switched between TR modes or turned engine off and then forgotten to turn off DSC again?
(I'm not being smart, it's just something that's happened to me).

No holes, sand was pretty soft and deep so it was relatively smooth. Climb was straight up. All was in the right mode as I'd only selected it all at the bottom of the climb.

Originally Posted by LRD414

Also, 3800 revs is pretty high and you mention being in high range.
Did this go on for long?
Could it have been a thermal issue, perhaps transmission?
Any other lights/symbols on the dash?

Don't think it was a thermal issue as drive to the dune was easy. The car wasn't struggling for power or slipping through the torque converter (hence 3800rpm) so not thinking a thermal issue. No other lights on dash either.

With more time i would of played longer to find out what works best but unfortunately it was getting late in the day and we still hadn't found camp.

There's no substitute for low range.

This is what I have found.


Always use low range in sand unless touring for long distances.


For sand hills, sand mode low range 3 or 4 is best, rather than auto mode. For more normal sand driving low range auto is good. If you put your foot down too much to maintain a lower gear in auto mode the car will cut power to try to maintain traction, or something like that known only to LR, even with DSC off. If you use a set gear you can keep the accelerator around mid range or less and still get heaps of power without the car deciding to cut power.


I recently did the hard track up Big Red and found the D4 flew over the top (backing off a lot at the top to slow it down) in either 3 or 4 low range with no run up at the bottom. I started in third and then changed to fourth which went the best on Big Red. No one else on the day I was there (four weeks ago) could get close to the top, even with long run ups. The closest was a Prado who copied my line after watching me do it several times with no worries. He got to about 10m from the top. All this was in my fully loaded D4 which weighs 2740 kg empty.


I will try to post a video some time if can work out how!

Originally Posted by MrLandy

There's no substitute for low range.

There kind of is though....

Low range 3rd final drive ratio 15.77
Low range 4th final drive ratio 11.85

High range 1st final drive ratio 14.76

Given all the elec-trickery things that happen behind the scenes on a D4, i wonder if there is a difference in TR settings between high and low range in sand mode?

Originally Posted by TuffRR

There kind of is though....

Low range 3rd final drive ratio 15.77
Low range 4th final drive ratio 11.85

High range 1st final drive ratio 14.76

Given all the elec-trickery things that happen behind the scenes on a D4, i wonder if there is a difference in TR settings between high and low range in sand mode?

Low range activates all the off road trickery and optimization in the D4. It makes a big difference. It is not just a simple ratio change.


I was once trying to drive fast along a beach at Esperance following my reckless son in law in his 80. He was on the wet part of the beach but I didn't want salt on the car so I was in softer sand higher up the beach. To keep up I used high range and after about 10 minutes of fanging the car along the beach it ground to a complete halt. Not sure why but I put it in low range and went my own speed with no problems after that.

Originally Posted by BobD

Low range activates all the off road trickery and optimization in the D4. It makes a big difference. It is not just a simple ratio change.

I'd agree for some modes, ie rock crawl, but did not think it made a difference in others ie sand and snow/gravel. Surely Land Rover dont expect you to drive gravel and grass in low range for the optimisations to work?