well i need to check into what whitetrash said that the ax15 is the same as the r150f, and if that is the case, you may be able to take your 5 spd tot tranny, use a jeep 4.0 bellhousing, and swap in the 4.0.....just need to do some research...b/c if that was the case, it would definitely be an awesome swap, while keeping the toy tranny, tcase, and axles
the spline count is different on the input shaft, you might just be able to use the yota clutch disc with the jeep pressure plate if you wanted to swap a jeep engine. IMO I would rather run the yota 5vz-fe (3.4) it has more power and can easily be superccharged.