Well the best thing to do, is to go there and inspect the car. But 235k km is a lot and the D40 has a few issues like chassis rust & timing chain. Make sure these have been taken care off, also it might be good to know if maintenance was done as required but also the automatic transmission, diff,...

As for towing, my previous D40 auto never had any difficulties towing anything, or hauling for that matter. Why not go for a little test drive and see for yourself? :cheers2:

 

provided the engine is still working ok then it will tow way better it will have between 400-450nm Torque the Mits engine is great for power but rubbish for torque as you have found out, as mentioned though check the chassis carefully they have been known to crack, i should imagine some of the washboards you have over there will only make things worse, if you do buy it get the chassis braced if your towing.
146000 miles isnt really a lot for Aus bear in mind the distances to travel, i lived in Malawi for a while and we used to travel to Botswana a every Month that was easily 4000km and am currently doing 1500 miles a month easily on our Tiny little island.
Looks very clean on the Pics no dents etc so its probably been sat on the Highway for long distances as mentioned test drive and budget/bargain for a duplex timing chain conversion

 

I'm on holiday for the moment in the France mountains with a caravan of with a total weight of 1800kg. The truck is a dream doing this kind of work. Even when going down the mountain there are times I don't have to touch the brake. The engine keeps everything on the track. Going up I even had to double a Mercedes Benz going from 30km/h to 60 in about 1.5 minutes. It surely whas I big climb up but the truck did a awesome job. The heat got up just a tad but nothing too worried about.