Automatic hubs got you locked out of 4WD? 

The automatic hubs used on the '83-'97 Rangers (and similar) are not the best thing to rely on when the going gets tough. They will click and grind and make ratcheting noises instead of engaging when you need them most. While the causes of malfunction can vary, swapping to a set of manual hubs is the easiest way to get reliable engagement. It can be done in 1-2 hours by the average at-home mechanic. The only special tool needed is a four-pin spindle locknut socket that can be purchased at any autoparts store. A hub conversion kit is also needed, available along with the hubs. It includes a new set of spindle nuts.

After jacking up the truck and taking the front wheel off, you may find some clips on the studs securing the hub to the rotor (sometimes these clips are absent due to either lazy service technicians, or wheel requirements). After removing the clips, the hub will come right off. Remove the half-round C-clip from the splined part of the axleshaft. Do not lose the splined washer ('83-'89 models will also have a thrust bearing that will be reused with the new hubs). Pull (or pry) off the plastic actuator cam. This won't be reused.

Remove the locking key from the slot in the spindle using a small, strong magnet. The wheelbearing locknut should be free to rotate (It will not be so tight that a simple pair of Channellocks can't loosen it). Turn the nut slightly if the key doesn't come out. Remove the locknut. It will also be discarded with the old hub.

At this point, it would be recommended to clean and repack the front wheelbearings with fresh grease. Make sure the grease you use is lithium based. Also, be sure to check the small needle bearing located in the back of the spindle for the axleshaft. These are often neglected by wheelbearing technicians. The spindle will need to be removed from the knuckle to get to it.

Take the new locknut from the conversion kit with the small pin on one side. This nut goes on first with the pin facing out. Tighten to 35 ft-lbs, then back it off and retighten to 15 in-lbs (or just snug by hand). Next is the locking washer (with the holes in it). Make sure the pin indexes a hole (turning the washer over will help if it doesn't line up. Don't loosen the nut). Now the outer nut. Tighten this nut to at least 150 ft-lbs. (I have found 200-225ft-lbs. to work better at keeping things tight. These nuts are known to back off if not tightened enough).

Reinstall the washer(s) (and bearing, if present) over the end of the axleshaft, then reinstall the c-clip (pull on the axleshaft, if needed). Slap the new hub on, put some new clips to hold it on, and you're done!

The manual hubs will not affect the operation of the electric shift transfer case. Just be sure to lock the hubs before you push the 4X4 switch.

One word of note,  
If you have aftermarket wheels on your Ranger, those retaining clips over the studs may create an interference problem. The stock rims have a recess around each lug hole. If the aftermarket rim doesn't have a recess, do not install the clips. The torque of the lugnuts will keep the hub in place.