Look here to ID what axle you have now:
https://therangerstation.com/tech_library/axle_codes.shtml
On the drivers door label
An OPEN differential provides power to the EASIEST wheel to turn, so in slippery conditions once one wheel starts to spin ALL power is transferred to that wheel, yes, probably not the best setup, but the least expensive for cars and trucks
A Limited Slip(L/S) differential uses gears or clutches to transfer power from faster spinning axle(wheel) to the slower spinning axle, so as one wheel starts to slip, spin faster, power is transferred to the other axle/wheel.
When you are driving the outside wheel, when going around a corner, must spin faster than the inside wheel so this type of differential must "slip" a bit or outside tire would drag, stop turning moment to moment to stay in sync with inside wheel or the axle will break
So its called a Limited slip differential, Ford calls theirs Trac Lok, Chevy calls it Positraction
These both use clutch packs
The gear type like Torsen are a bit better, but for light use the clutch packs are fine
Locking differentials are for specific use, there will be a switch or lever in the cab to Lock rear differential, so both axles/wheels must turn at the same speed
This prevents any cornering, except on low traction surfaces where a wheel can drag easily.
This wouldn't be practical for general street use, but very cool to have
Most Ranger 4WD models came with L/S rear axles(not all) and you can bolt any year Ranger axle into any year Ranger, 1993 and up were wider axles, 1" wider on each side.
And Ranger 7.5" or 8.8" axles can be swapped no difference in install
Explorer axles need to be modified
Front wheel drive(FWD) is the main reason 4WD in trucks works better
Pulling a load is much easier than Pushing a load
This is why FWD cars do better in the snow than rear wheel drive cars or trucks, even though FWD is an OPEN differential.
Yes, the weight of engine above the drive axle is good but the Pulling of the car's overall weight is what makes the difference.
Rear wheel drive cars or trucks can be loaded up with weight over rear axle and still not do as well as FWD, pulling the weight is the key
A rear wheel drive with limited slip axle is better than OPEN, but it is still Pushing the weight of the vehicle, so front wheels will tend to dig in to snow or mud or ??, instead of being Pulled above it
If you have 4 wheel vs 2 wheel drive then you have twice the chance of one wheel getting traction in slippery conditions, so as for a rear wheel drive with limited slip or locker going where ever a 4WD can go its not true BUT...............
Most places people with 4WDs go are not like that, so yes, with a Limited Slip rear axle and a winch you can go off road with some confidence.
But again, in mud your front wheels will dive into the mud and rear wheels, limited slip or locker, won't be able to Push them out.
I don't know if you remember the old days, but its still applicable today, when all cars and trucks were rear wheel drive in some situation you would have to Back up a hill in Reverse to get to the top, Pull the car up the hill vs trying to Push it up the hill