Marlin has a Toybox for FJ62s so that would mean the rear adapter for that should mate a Toy-mini range box to the Cruiser splitcase. That way you could retain your 4 cyl clutch and tranny...
Might be easier to build that centered rear diff Hybrid and keep the toy-mini drivetrain.
![I Dunno... :dunno:](https://board.marlincrawler.com/Smileys/marlin/dunno.gif)
Do you already have a crawler in your rig?