Does it steer properly now? If so it's just a full-size seventies vintage gearbox. If it steers correctly with the pitman facing front like that, then it's not actually a "4x4x2" box and would have to be converted to one, like Rustytruck said.
The way it's mounted looks like reversing the pitman arm might get you into some interference issues with the linkage.
Did you buy the truck this way just recently? Or have you been driving it for awhile already?
Paul