1998 Mazda B3000 4X4 SE Rear end?

How would I go about finding what type of rear-end is in my 1998 Mazda B3000 4X4 SE Std cab? I know my gearing is 3.73 but i don't know if its LSD or not. Also I don't know the maker of my rear-end i.e. ford or dana or etc.