Outer Limits 4x4 Board

I use 660 bronze to machine new the bushing from. The few I have made have lasted longer than the original output bush.
Actually I have not replaced any that I have made in the past 30 years.

If you rely on a fan switch in the outlet the engine temperatures will not be stable since the water has to rise above the thermostat temperature to get the fan to cycle.

The fan will respond better if the switch senses the return water temp. This has the fan run only when the radiator can not do ...

The rear center should swap right in as well as the front. The front will be a low pinion as your truck is.
The 4.22 are common in the 4WD, 3.9 is found more in 2WD and might be hard to find in the 9".

The LSD is very easy to swap from one gearset to another. It is about ½ hour job once the unit ...

This one is a relatively inexpensive fan, no brand name unit. I install fittings into a end tank of the radiator with a 16mm thread to install the thermo switch and wire them with a relay so the fan can run with the key off.

I run electric fans on most everything I build. here is my 95 3.5 with an alloy radiator and electric fan setup.

If you take a look at the L200 of a similar production year you will find the 4.22 ratio that will go in your Montero. There is also a 3.9 available but probably just in the smaller axles.

This will not be a whole axle swap you will need to do just the 3rd member.