Any ideas why it is not permanent 4WD? In this day and age part time 4WD does seem like ancient technology.
Because the overwhelming volume of 78/79 series are sold to the mining and oil companies for extended operations in harsh conditions.
While full time 4wd technology has improved,it will not stand up to the abuses dished out underground.Ask anyone who fixes them for a living.
All the alternatives have been tried and retried and the drivelines are just not up to it. In some places they go through 3 other vehicles to one 7* series.
One mechanic reported recently that the 79 series at his mine had a maintenance bill of $4000 dollars a month for each vehicle.Other vehicles that were tried ended up as landfill in 2 months.
Its not ancient technology if there is nothing around to replace it.