Alex, I don't know what angle would be max, but even a small angle over the rocks, the diesels do seem to keep a more consistent rev, where as the petrol ( and I remember this with my 3.0 Sani ) the revs were up-down-up-down, as you had to feather the throttle over a bigger rock, then foot off a bit to slow down. So your rev range is probably between lowest 500 up to say 12 - 1300 rpm. On the old 4.2, the flywheel is so big that the revs vary between 700 and 1000, keeping a more steady speed. Obviously an auto box on a petrol Patrol or any vehicle will do the same to a degree, but the auto box will also allow the vehicle to come to a stop up against a rock, to which you need to depress the accelerator further to get it over. Once over you have to take foot off quickly to slow you down ( like getting whiplash....

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But the fact is that in soft sand you petrol guys eat us diesels for breakfast..... but on the rocks diesels are just made for that terrain, and kick butt.