They had to or should have, doesn't mean they did. Then again reality of US market is that 90% of vehicles will never see anything more then gravel road. Xterra was specifically designed for US market (only sold here as well) so they prob didn't foresee great need to over-engineer it. Plus cars/trucks are extremely cheap overhere so manufactures have to cut cost as much as possible. Putting light duty DANA 44 in rear of 300 hp full-size pickup. Makes you scratch your head, what were they thinking. I remember reading 4Wheeler magazine just after Titan came out. They had one in long term test. Rear end blew right away after which they put DANA 60 in there.

Patrol is great vehicle in many respects (truly stout drivetrain) but had it share of disasterous failures specifically with 3.0L TD most commonly found in later model. They pretty much discontinued venerable 4.2L one. Don't know what they were thinking.

Also of how many rear diff failures you've heard on Trooper or Montero under similar condition. I'd say close to none.