im thinking that the 13 tooth gears are going to be the ones on the splined end of the axle and the 9 tooth gears will be held into the case with the big pin in the middle. the wheels will spin at what ever speed they need to, the gears will have no affect on which one goes faster, the only time one tire spins faster is through a corner. the tire on the outside of the turn, the tire with a longer radius has a larger circumference to travel than the inside, so it will spin faster.
or if you are sitting still pullin a one tire fire, while wishing you had bought a posi, one tire will definitely be spinning faster.
or if you are sitting still pullin a one tire fire, while wishing you had bought a posi, one tire will definitely be spinning faster.