IAM-SO-sLOw

i got a problem like i bought a stock lsd pumpkin and output shafts off a junkyard and when i try to put it in my car. the axles that came w/ the lsd dont fit in my car. one side is too short and one side is too long. like i thought i put them in backwards but no. one side is still too long and one side is too short. does anyone know what i can do. the person at the junkyard told me it came from a 240 or 180 but i have a feeling it might b from a 300 does anyone know what i can do to make it fit?