New D-Max

Had ours for about 3 months and 7000 Ks a little bit of off road and nothing had fallen off so far. I have had Isuzu vehicles for around 12 years (imported ones MU and MU Wizard) which have very good build quality, and I believe the D.Max is built very well also.

My 2008 Colorado (isuzu) has been to all the places you mention. It has been boringly reliable for 120000 kms thus far, despite various dealer's best efforts to do it in (joke). The tub tray has split (abuse - overloading the canopy on corrugations - still works though) and the EGR valve has been replaced. That's it warts and all.
The new dmax is still using the same 4jj1 engine which has been perfect, teamed with an auto box. It's a bit down on the outputs of the new ford/mazda, colorado, VW etc., but it is still a worthy donk with runs on the board in the reliability stakes, which the others have yet to prove.

MarJac
The new Dmax and the Colorado are basically the same vehicle, chassis and body, Sheetmetal is different and engine, powertrain is different too.

All the common utes aren't really strong but used wisely will do a good job.
The Colorado claims more power and torque with a smaller engine while the 3litre Dmax claim is less it is also less stressed while working.

Most Dmax seem to stay together ok and other makes seem to have proportionately more trouble.

You have probably only driven it and others on bitumen roads so the "feel" on the tracks you mentioned will be quite different.

Any vehicle claiming big torque and big horsepower will also use more fuel to provide that energy while operating at that level so towing loads are something to be considered.
Only testing with a load and feedback will give you some idea of expected fuel use while towing a load.
Yes they will pull 3 ton or 3.5 ton or even more if the manufacturers can stake a claim to being the greatest.

If you go and look at the section size of the rear of the chassis on most of these types vehicles you will be disappointed to see all the towing is via two slender chassis sections to which the BIG towbar unit is bolted to, and of course your expensive caravan hangs on that. To overload that is unwise.

All salemen/women from all makes aren't engineers but do give advice as to the strength of the chassis. I don't wear rose coloured glasses so don't see the same capabilities as they readily accept.

If it is rated at 3ton and you want to travel with some degree of safety and some reserve capability and especially if it is used on rough tracks, my view is not to exceed 2/3 of the stated amount the manufacturers claim their vehicles will operate at.

Hi MarJac
We bought a Dmax because of it's good reputation and a couple of friends have them as well and have given them a flogging here in the NT and they have proven to be well screwed together and reliable.

I did a bit of a write up on my brief ownership experience of the new Dmax in this forum if you are interested. Thread 97572. Glad I bought it and wouldn't have anything else.

Happy travels.

Thanks to all for your comments. They sound like a good thing. I just have to screw the dealers down now.......