My 1994 auto hubs are still working fine, original parts
BUT..............you do need to clean the parts and keep the wheel bearing grease OFF of them, just a light oiling to keep them lubed.
People often think the hub cover is a "Grease cap", lol, it isn't, grease belongs in the wheel bearings, keep it there
So first step is to confirm front drive shaft is turning in 4WD
Have some one watch front drive shaft while you move vehicle forward or backwards while in 4WD
If it is not turning then problem is in transfer case
If it is turning then jack up the front wheels pull off the tires and cap, clean the auto hub parts, oil them and reinstall.
Any obviously broken pieces will be hard to replace so look at Manual Hub conversion
And manual hub conversion would be best in any case if you NEED 4WD, "auto" anything is by its nature has to be less reliable than "manual", strictly a convenience choice.
Auto hubs work by the front drive shaft turning, when drive shaft turns the front axles it engages the auto hubs, when 2WD is selected the drive shaft and axles are no longer powered, so "drag" the auto hubs back to disengaged position, you often have to backup 20-50ft to get full disengagement, depends on last time the parts were cleaned.
"Clicking" noise means one hub is not full disengaged, or engaged, if going into 4WD
Stock front axle/differential is an OPEN type, these means the easiest axle/wheel to turn gets ALL THE POWER
So if one auto hub locks but the other does not, then no 4WD, because the unlocked hub gets ALL THE POWER, it is the easiest axle/wheel to turn.
OPEN is the most common axle setups, front or rear, this is why only 1 wheel spins when cars get stuck, easiest wheel to spin gets all the power
4WD Rangers often have Limited Slip rear axles, so BOTH wheels get power, but front is always OPEN type
Also shift into 4WD high, 4low and back to 2WD once a month, you don't have to move the vehicle, you are keeping the shift motor brushes clean and the lube inside spread out.
Problem with electric shift is that it often sits for 6 to 8 months, so may not work when you first use it for winter driving