got it figured out on the axle problem, come to find out theres 2 axles in all the rear diffs that are the older style like what was used in the bajabandits, hoppers, blaster, and wild things whether 1 wheel spins the opposite direction or even if its a posi type where both spin the same direction.
the difference is how the left axle connects to the gear in the middle that attaches the two axles. on the posi type, both axles slide into the center gear with a hex type fitting like the wheels have, that locks them both in place, the other style instead of using a hex on the end it has a gears, that gear spins inside of the big gear which has 2 small side gears and when these are sping the spin the other half of the big gear that the right axle is connected to.
as for my diff that only 1 wheel was spinning, the plastic piece that the right axle slides into with the hex shape had stripped out a bit, but luckily that big gear comes apart and i was able to use the piece from the other style diff to fix it.
i also found out that the older style rear diffs with the small lever for hi/lo that hangs off the back of the gear box like in the blasters, older baja bandits and hoppers, they dont all have the same gear ratios, the bandit from what i could tell had lower gears than the blaster does, but im not sure if that is one difference in the open-and locked diffs- or a difference in which car the diff was going to be used in
now the newer style diffs like the eliminators and newer bandits had are a different animal, they are a solid axle, and i dont think ive seen any that style that have a differential.