This is a front axle and rear third member. Only 2 holes line up. I emailed them last night.With both axles facing forward (or backwards) the ring gear is on the same side of the pumpkin on both axles. When you position the axles so both pinions are facing each other is when the ring gears oppose each other allowing the drivetrain to turn. I don't see any differences in the third members (but I'm probably missing something?) other than the front has a side hole for a shock mounting screw but you could easily fit a lock nut there. Please clarify if I'm missing something so I can understand what is actually going on here.