Factory Manual Hubs
 

Toyota has always offered manual locking hubs on all of the trucks they have made over the years.  If you couldn't order your specific truck/4Runner with manual hubs, you could change to manual hubs later.  Manual hubs are extremely easy to identify, they have a dial on the end of the hub so you can lock or unlock them as you wish.

Toyota has always used Aisin manual hubs.  They are the best available hub on the market for your Toyota.   Their quality and strength surpasses all aftermarket hubs.  Unfortunately, their price also surpasses all aftermarket brands.  Buying a 'new' pair of Aisin is out of the question unless you just won the lottery.  If you need to replace a hub visit a wreck yard and buy a used Aisin,  or get a pair of new aftermarket hubs with a lifetime warranty.

With manual hubs, IF you have both hubs LOCKED, you will be able to shift into 4WD at any safe speed.

ADD 'Fixed' Hubs
 

Here is the ADD hub.  You'll find this hub on ADD equipped trucks (1989-current) and 4Runners (1990-current).  ADD hubs are nothing more than a locking plate that keeps the axle locked to the wheel.  There is no way to 'unlock' an ADD hub.  The ADD system is its stock form is capable of shift-on-the-fly. 

Please visit the ADD page for more information on these hubs.

Factory Automatic Hubs

Here is the AUTO hub.  It can be found on trucks from 1984-1988, and on 4Runners from 1984-1989.  Do not confuse this with ADD (automatic differential disconnect).  AUTO hubs are NOT similar to ADD.  The AUTO hub has a clutch inside that will lock the hub when it receives forward movement of the axle.  Since the axles are not always spinning with this design, you must come to a COMPLETE stop before shifting into 4WD.  Under no circumstances can you shift into 4WD while in motion with the AUTO hubs.

The AUTO hub will unlock after 1/4 turn of the axle in reverse.  This is the major flaw to the design.  Often on the trail we need to back up in 4WD.  Especially if the vehicle is stuck, and we're trying to free it by backing out of the hole it is in.  With the AUTO hubs, once you shift into reverse and begin to turn the driveline the hubs will unlock, and you'll be left with only 2WD in reverse.  The will eventually lock into 4WD again...  but having them unlock on you at all is very troublesome.

This hub is notoriously unreliable.  The springs inside the hub often break, and the hub will no longer engage.  Repairing these hubs is VERY expensive, and replacing them with new AUTO hubs is out of the question... you need to take out a small loan just for the down payment on the hubs.  (okay, okay, I'm exaggerating a little... but the price is still in the hundreds of dollars)

The best thing you can do is to replace your AUTO hubs with manual locking hubs.  You will increase the reliability of your 4WD system many times over by getting rid of the AUTO hubs, and you will gain the ability to shift-on-the-fly, assuming you're driving with the manual hubs LOCKED.

Switching to Manual Hubs on a Toyota 4WD with factory AUTO hubs

Tools Needed:
-12mm socket
-Set of allen wrenches
-T-20 Torx bit
-54mm socket

Installing manual hubs on a truck or 4Runner that has ADD hubs is easy.  You simply unbolt the ADD  hub and bolt on the new hub.  It is not even necessary to remove the wheel from the vehicle.  Switching from AUTO hubs is significantly different.

Pictured is the 'install kit' required to switch from AUTO hubs to manual hubs.  The kit is available from the same shop you would buy the hubs from.  You can also just purchase the parts from the Toyota dealer, which might save you a few dollars.  The kit consists of four 54mm nuts, two larger washers, and two locking washers.  If the dealer pulls up the exploded diagram for a truck / 4Runner with manual hubs these parts should be easily identifiable. 

Also pictured are a pair of new Warn Premium hubs.  This is usually the hub of choice for people converting over to manual hubs because of the price and warranty.  The hubs usually sell for approximately $130/pair, and Warn hubs come with a lifetime warranty. 
 

To begin removing the AUTO hub, take off the auto hub cover and remove the 12mm bolt & washer from the end of the axle.  Remove the six 12mm nuts and cone washers that are holding the hub body in place. Pull off the hub body. It may be necessary to tap the hub body with a hammer on all sides to get the cone washers to loosen.
 

Compress the spring with a pair of pliers and move it  around so that you can get a size 20 torx bit in to remove the three torx bolts and remove the auto hub clutch.  Remove the 54mm nut.  You'll now be able to see the outer wheel bearing. 
 

Install the large flat washer against the outer wheel bearing.  Install one 54mm nut.  Torque to 18-20 lbs.  Install locking washer.  Install 2nd 54mm nut.  Torque to 58 lbs.  Bend the tabs on the locking washer to prevent either nut from loosening.
 

Put the new hub in place.  Install the six 12mm nuts that hold the hub body in place.  Install the 12mm bolt and washer you earlier removed from the end of the axle.  Install the dial on the hub using the bolts provided with your hub. 
 

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