I think you'll need a 3.5 Sport to get the 8" diff.

I am told that they will not swap directly if you want to use the CAD from the Sport. However, looking through the Sport service manuals, the diesel version that we never got looks like the same CAD setup as the Gen II Montero, but with the diff like the Sport. I plan to get them side by side and see what I can swap. It would be easier than doing gears.

On the rear, I am going to pull the Sport 4.90 third and see if I can drill it for the locker air line. That way I'll only have to swap the 4.90 ring gear onto my locked carrier, and not have to mess with the pinion.