How do I know if automatic hubs are working properly?

[broncAR]

I live in Buenos Aires, Argentina and after many years of searching six month ago I bought a 1986 Bronco XLT EFI . I’m still learning how to ride this beast but my experience in other fields tells that all automatic stuff stops being automatic in the worst moment (that is, when you really need them). I saw many advices as to change auto hubs for manual ones, but before doing so I’d like to check if the original ones are working and get to understand how do they work. Does anybody know how do auto hubs work in my ’86? How do I check if they do work as they should?
Thanks

[Gacknar]

How to test Ford Auto locking hubs on all TTB aplications.

1. Place transfercase in 2HI or Neutrall.

2. Lying under vehicle, turn front drive shaft (one direction only).

3. Automatic hubs should lock after 1 to 5 turns of driveshaft (one direction only).

After step 3 the hubs should lock, youll know they are locked becouse you will hear a click from both hubs and you will no longer be able to turn the front drive shaft (in the same direction). If this is not the case then continue to step 4. If you can no longer turn the drive shaft (in the same direction) then skip to step 7.

4. If you can still turn the drive shaft (one direction only) then one or more of your Auto hubs is not working.

5. Continuing to turn the Drive shaft (one direction only).

6. Look at the u-joints for the front stub axles, if both are turning then both front hubs are malfunctioning, if only one is turning then the one that is not turning is locked and the one turning is malfuctioning.

Replace as necosary (preferably with manual hubs, Auto hubs have Yams in them)

7. To unlock the hubs, turn drive shaft in opisat direction untill you hear a click from the hubs.

To check for transfercase engagement.

1. Place pushbutton transfercase in either 4 HI or 4LO.

2. lie under vehicle.

3. You should not be able to turn front drive-shaft in either direction.

4. If you can turn the front drive shaft then your transfer case is not shifting properly.
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[Washburn]

Damnit! I was just about to give that link, had to find it first...

[Pony-boy]

Damn, Gac is on it today

[lightnin]

I thought you knew they were working when you replace them with Warn Premiums.