Thread: Terrain response while towing offroad

Thanks all

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.

Originally Posted by 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.

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!

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

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.

Originally Posted by 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.

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

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.

Originally Posted by BMKal

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

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 . Don't leave home without one.

Andrew