Note that driver's side/passenger side varies throughout the world! For our discussion here, the driver sits on the left side of the truck.
The ribs on the rear diff thirdmember make me think it's not the "normal" 8" diff, but my understanding is that the Hilux running gear was the same as the preTaco, about a generation behind what we got here in the USA. For example, solid front axles were available until (at least) 95.
ariman - If you could take a pic of the front diff, we could tell a lot. If it's the older "chunk" version, it will be easy, if it's the newer "clamshell" version, it might take some more research.