Terrain response while towing offroad

[wbowner]

Hi
Is there any article or documentation around that discusses terrain response settings while towing

Eg
If towing a van offroad in say Vic high country what Terrain Response settings would you recommend


WB

[BobD]

When I tow in low speed very rough, steep and windy tracks (not as bad as Vic high country) I use high range and sand mode. This gives the car better gearing (keeps the revs up) and better engine mapping for the steep hills and slow speed (40 to 80 kph). If really slow I would use low range sand mode.

For maximum traction really slow speed I would use rock crawl. I never tend to use mud and ruts or gravel and grass for anything, rightly or wrongly. However, I hardly ever drive in mud. I might change my mind if I did.

[wbowner]

Thanks Bob

[wbowner]

A follow up
do you ever use low range towing on the bitumen

Read in the forum some where you can but they talk about not locking the CDL.
Unfortunately you don't have that control in the D4 I believe


WB

[RobA]

Really the answer is it all depends. If you mean on the dirt roads and fire trails we just use LR and leave TR alone as it is not required. On really steep descents though we will use HDC and manual mode selecting first or second LR depending on how much engine braking we want. As well we change the settings on the brake controller to push more braking effort to the camper.

If you mean really off road either sand or rock crawl mode as you are probably already in LR

Rob

[wbowner]

Rob
Talking about on road bitumen

Apparently according to FAQ D4 don't get wind up if driving in low range on bitumen.

WB

[Bytemrk]

Apparently according to FAQ D4 don't get wind up if driving in low range on bitumen.

WB

I believe that's true..... in a D3/D4 the system will only lock the centre diff when it senses a a loss of traction at one end or the other, no matter what surface you are on. ( Unless you put it in rock crawl I think.) Vehicles where you manually select the CDL it's either on or off - the vehicle has no way of knowing if it's needed or not - that's why if you select it in the wrong situation you will get wind up


I don't tow a lot - but I nearly always use low range to reverse trailers , no matter what surface I'm on. I wouldn't be worried about low range on bitumen - I'd be more careful about use of terrain response settings.

[BobD]

You can use low range or any traction control settings on bitumen if you need to. The car won't allow itself to be damaged by too much locking of anything, whether centre ediff or rear ediff. You wouldn't normally need low range, however, apart from backing or perhaps improving engine braking at very low speeds. On steep low speed hills you could use low range to reduce the stress on the auto transmission, but that would not be normal for most bitumen roads.

[Tombie]

And in answer to your question- get the booklet from GOE and have a read [emoji41]

[Tombie]

Mark, you can use any TR setting..
Give Sand mode a crack off the lights one day [emoji6][emoji6][emoji6]

[Bytemrk]

It was only Rock Crawl which concerned me...... but the great thing about this place is you learn something new every all the time!.


Hmm.. sand mode off the lights you say..... would that have saves the rear drive shaft I broke ?......[bigwhistle]

[wbowner]

Thanks all

[Milton477]

I suspect that not all is documented.

I had an occasion recently to follow the path of a water pipeline up some very steep grades. Some sections are concreted because of the steep angle & I chose to use low range, no special programs. While ascending, I watched the 4x4 screen & noticed that the depending on the angle, the E diff locked, sometimes partially. There was no loss of traction at the time as the surface was concrete.

The second time I drove the same route, I used high range sport so that I choose & maintain gears. Going up the same grades in 1st high did not lock the E diff.
I recon these vehicles are smarter than we give them credit for.

[Grentarc]

I suspect that not all is documented.

I had an occasion recently to follow the path of a water pipeline up some very steep grades. Some sections are concreted because of the steep angle & I chose to use low range, no special programs. While ascending, I watched the 4x4 screen & noticed that the depending on the angle, the E diff locked, sometimes partially. There was no loss of traction at the time as the surface was concrete.

The second time I drove the same route, I used high range sport so that I choose & maintain gears. Going up the same grades in 1st high did not lock the E diff.
I recon these vehicles are smarter than we give them credit for.

The E-Diff and centre diff are locked preemptively so that you don't lose traction - which is why it is an active differential system rather than a reactive system.
They have been programmed quite well, that's for sure!

[LandyAndy]

I confused my terrain response the other day.It doesn't have a setting for driving onto sleepers!!!!
Drove into the shed put 2 sleeper blocks in front of the front tyres with ramps onto the blocks.Selected low range and nothing else,the terrain response spat the ramps one after the other,only gentle throttle application,didnt expect that.
Set it all up again,rock crawl,1st sport.Did what I wanted the first time.
Andrew

[Graeme]

The centre and rear e-diffs don't necessarily show locked on the display when pre-armed, eg selecting reverse while in rock crawl pre-arms the rear e-diff to a lesser degree than when selecting D or S and displays as unlocked. Locking for both the centre and rear e-diffs also takes into account the direction of the front wheels.

[BMKal]

The centre and rear e-diffs don't necessarily show locked on the display when pre-armed, eg selecting reverse while in rock crawl pre-arms the rear e-diff to a lesser degree than when selecting D or S and displays as unlocked. Locking for both the centre and rear e-diffs also takes into account the direction of the front wheels.

This is exactly what I was seeing when I had my recent issues with the centre diff locking up. [wink11]

The only time that I could get the centre diff to show as locked on the display was when I selected low range, rock crawl mode. When the centre diff was engaging in high range and producing the shuddering and "grabbing" feeling when the steering was turned close to full lock, there was no indication on the screen that the centre diff was locked. The problem existed regardless of whether I was moving forward or in reverse, though it seemed to be more severe in reverse. The only way that I was able to resolve the problem was by running the two calibration sequences using the IID Tool. I have had to do this twice now, and the problem has not returned (touch wood) since the second calibration.

I still don't really have a clue what was causing the issue. I suspect some water may have got in somewhere after driving through the flooded streets at the time, but I have been unable to find any evidence of this. Interesting that you say "locking for both the centre and rear e-diffs also takes into account the direction of the front wheels". While I have no way of knowing for sure whether or not the centre diff was remaining locked when the wheels were straight, the problem was certainly only noticeable and seemed to be "triggered" only when the wheels were at close to full lock. I suspect though that once the problem was "triggered" and the centre diff was locked, it remained locked until you shut down the engine (you could actually hear it dis-engaging a couple of seconds after the engine stopped). I'm wondering after your comment whether one or both of the steering angle sensors may have contributed to the problem - though it seems that they have always been functioning correctly.

[AndrewM]

This is exactly what I was seeing when I had my recent issues with the centre diff locking up. [wink11]

The only time that I could get the centre diff to show as locked on the display was when I selected low range, rock crawl mode. When the centre diff was engaging in high range and producing the shuddering and "grabbing" feeling when the steering was turned close to full lock, there was no indication on the screen that the centre diff was locked. The problem existed regardless of whether I was moving forward or in reverse, though it seemed to be more severe in reverse. The only way that I was able to resolve the problem was by running the two calibration sequences using the IID Tool. I have had to do this twice now, and the problem has not returned (touch wood) since the second calibration.

I still don't really have a clue what was causing the issue. I suspect some water may have got in somewhere after driving through the flooded streets at the time, but I have been unable to find any evidence of this. ....

The centre diff locked up in my D3 after getting water in the transfer case crossing Nolans on the OTT. To this day I don't know how the water got in as it is supposed to have a breather high in the engine bay. Maybe it sucked in through a seal somewhere, although we'd been through plenty of water on previous crossings. I didn't have a center display so I could only guess as to the problem, but the wind-up and clunking was pretty bad on full lock, the same symptoms I had in a SWB Pajero in the 1980s.

The diff stayed locked until the oil was changed and the diff re-calibrated in Cairns.

I now have an IID [smilebigeye]. Don't leave home without one.

Andrew

[BMKal]

The centre diff locked up in my D3 after getting water in the transfer case crossing Nolans on the OTT. To this day I don't know how the water got in as it is supposed to have a breather high in the engine bay. Maybe it sucked in through a seal somewhere, although we'd been through plenty of water on previous crossings. I didn't have a center display so I could only guess as to the problem, but the wind-up and clunking was pretty bad on full lock, the same symptoms I had in a SWB Pajero in the 1980s.

The diff stayed locked until the oil was changed and the diff re-calibrated in Cairns.

I now have an IID [smilebigeye]. Don't leave home without one.

Andrew

Have checked the oil in the transfer case - no sign of water and the oil level is correct (oil is very clean). I suspect it more likely that water has got into an electrical connector somewhere - though I have been unable to find any evidence to support that view.

One thing that we did discover which may come in handy for anyone who has a similar problem and does not have immediate access to an IID Tool - there are two electrical connections under the transfer case. If you disconnect one of these, the centre diff will unlock (you can hear it dis-engage and when you move the vehicle on "full lock" the wind-up and clunking will be gone) and will not lock again until that connector has been plugged back in. Limits the capability of the vehicle a bit, but I would rather do this than drive the vehicle any significant distance with the diff locked. [wink11]