Manual Hub Conversion for the 1st Gen Tacoma & 3rd Gen 4Runner

Correct.

Using your own spindle is also beneficial because some spindles have the ABS tab, and others don't.

There's the clamp mod too if you've got the ADD diff end, where you use the clamp to keep it in the 'engaged' position.

 

Ive ran the past 6+ years without the clamp mod, I just lock the hubs before going offroad, then pop into 4wd when needed. Always worked fine, then enjoy the freewheel during normal driving.

 

I do the same. It’s nice to be able to lock your axles manually and have ADD work as it normally would. If I forget to unlock them it’s not doing any harm.

 

Thanks guys to clarify. I appreciate it.

 

No bother at all. Looks like the good people of TW got your back!

 

@DJB1 i completed the conversion process replacing hubs, seals, spacer, nuts, cv axles and adding free wheel hub. My concerned is about removing the gear that you take off when you removed the intermediate passenger shaft, the person that help me to do it with “mechanic knowledge” never removed that gear, he left installed, just left the 4wd engaged, turn off the ignition key, installed the clamp in the fork actuator and removed the wire harness.
That gear needs to be removed? If so, what’s the consequences that can I have for it?
Thank you,
Juan

 

That gear needs to stay in place if you're keeping the ADD actuator. Your friend that helped you did it correctly.

 

Nice write up! I'm getting ready to do a 4x4 swap in my 01 Tacoma, I've got a J shift transfer case, the earlier Tacoma non ADD front 3rd member and a set of cv axles. Can I install locking hubs on my knuckles? Mines a Prerunner and already has 4x4 knuckles.

 

@DJB1 thanks for your help, I appreciate it.

 

I need to do this. It has been a royal pain with a lunchbox locker in the front needing to unlock my hubs everytime i want to go on pavement lol

 

The steering knuckles are the same but you'll need new wheel bearings. This guy's got the rundown:

https://www.youtube.com/watch?v=TZ2sOfVrnhU

 

Like lots of people, my weakness for Toyota trucks started during the neon vomit paint and non-functional chrome suspension craze of the 1980s and early 90s. I liked that style but preferred low-spec beaters, especially if I saw them covered in red dirt returning from adventures that looked as white trash as our own. So of course I’m going to like modifications that remind me of the old gods of Toyota 4X4 history. I still have impure thoughts when I see them:


I had several reasons for wanting to convert my 1st Gen Tacoma from ADD (automatic differential disconnect) to manual hubs. In order of importance:

1. I scored a complete manual hub front axle assembly super-cheap from online classifieds. The steering knuckles, wheel bearings, CV axles and upper ball joints were all in good condition and reuseable.

2. I want to avoid weird vibrations and rapid CV axle wear when I get a suspension lift.

3. If the front differential or a CV axle breaks, I can unlock the hubs and freewheel back to civilization.

4. I get 2-LO with no further modifications.

5. Some who have converted to manual hubs claim a 2-4 MPG improvement, since the CV axles don’t turn in 2WD like they do on ADD trucks. I track my fuel economy anyway, so I’m interested to see if this is true or just internet hype. EDIT: I saw no MPG improvement but this is still one of my favorite mods.


Here are the additional parts I used:

E14 External Torx socket
M12 X 1.25 Bolt with washer, 35MM long (quantity 4)
Upper Ball Joint Boot Kit: 43324-39015 (quantity 2)
Inner and Outer Aisin Hub Gaskets: 43531-60010 (quantity 2) & 43422-60060 (quantity 2)
Aisin Hub Dial O-Ring: 43532-60010 (quantity 2)
Right front axle seal: 9031147010
Left front axle seal: 9031147011

Time to make a mess:


Steering knuckles are the same either way, but the wheel bearings are different. If you want to do this the hard way you can get non-ADD wheel bearings pressed into your existing steering knuckles, then source the Aisin hubs and non-ADD CV axles separately. But it's a lot easier if you have complete assemblies:


I would have swapped these in without taking them apart, but the locking hubs were stuck so I had to rebuild them. This thread and diagram were helpful:
http://www.yotatech.com/f116/aisin-locking-hubs-tear-down-build-up-158644/

The top row is incorrect and looks like Haynes mixed up the 1995.5-2004 Tacoma and 1986-1995 "Pickup" locking hubs. But the bottom row is accurate. Only the Tacoma-specific Aisin hubs with gray dials will fit Tacomas and 3rd Gen 4Runners. The older Pickup/4Runner Aisin hubs with red dials are not compatible. I painted my hub dials red for that vintage Toyota 4X4 look.

Hang the brake caliper out of the way just like when you change pads and rotors:


A 3-jaw puller will pop the upper ball joint loose WAAAY easier than beating it with a hammer. Notice I left the castle-nut partially threaded so the steering knuckle won't flop out and hit me in the gonads. Support the lower control arm with a jack, then take out the bolts for the lower balljoint. That way you can slowly release the strut tension:


If you still have a sway bar, move the end link out of the way or you won't be able to pull out the CV axle. The CV axle pops out easy if you use 2 pry bars at the same time on opposite sides:


Then when you take the castle-nut off of the upper ball joint, you can pull the steering knuckle and CV axle out at once.


The intermediate shaft has a frame bracket with 3 bolts that take a 19MM socket. Behind that are 6 E14 external torx bolts holding the intermediate shaft/ADD actuator on the front diff. If your front diff has never been apart before, these torx bolts are going to be brutal. I would strongly recommend having a set of broken stud and bolt sockets, in case you strip one of these like I did.


Here is what the front differential looks like with the intermediate shaft/ADD actuator assembly removed.


If you have a J-shift transfer case and have to reuse your ADD intermediate shaft:

Key on the ignition, shift into 4-HI and key off. Unplug the ADD actuator from its wiring harness and disassemble it. Put a hose clamp on the shift fork to keep it permanently engaged in 4WD and reinstall everything on the front diff. The hose clamp needs to be wide enough that the shift fork can't move. If you skip this step, your passenger side CV axle will not be connected to the front diff even if the locking hub is turned in. Leave the wiring disconnected so the ADD actuator doesn't burn up from attempting to shift in and out of 4WD. The ADD wiring harness can be unplugged near the starter and removed from the chassis harness.


If you have a J-shift transfer case and a non-ADD intermediate shaft:

Use the double pry bar method again to remove this gear. It has a spline and snap ring just like a CV axle. Then the non-ADD shaft fits like it was meant to be there:

Notice that I used normal M12X1.25x36 bolts instead of the stupid torx bolts. This is also a good time to install new axle seals.

If you have a pushbutton transfer case:

Leave the ADD actuator in working condition because that's what the 4WD button operates. It's the only way to shift in and out of 2-HI and 4-HI while driving. You can't have purely mechanical 4WD like us cool J-shifters, but you can still unlock your hubs for normal daily driving and greatly reduce drivetrain vibrations and CV axle wear. Thanks to @Buck18 for sorting this out.

Now you can reassemble the CV's and front suspension. Green CV axles are for ADD and blue ones are for manual hubs. The inner CV shafts are the same but the outer shafts at the wheel end are different. The easy identifier is manual CV's are splined all the way to the end, ADD CV's are threaded at the end.

Manual:

ADD:


There's also an easy identifier for manual vs. ADD differentials if you look at the left side. But it doesn't matter too much because they're interchangeable.

Manual:

ADD:


There are some myths that are frequently recited by friends and internet forums. One is that on ADD systems only the driver's side CV axle turns while driving in 2WD because it's permanently engaged to the front diff, while the passenger side CV axle only turns in 4WD. Here is my ADD CV axle and passenger side front hub. The splined section where the CV axle goes in is part of the hub and can't turn independently:

So on ADD front ends it doesn't matter if it's in 2WD or 4WD. If the truck is moving both CV axles are turning.

The other common myth is that with manual hubs you can no longer "shift on the fly," or shift in and out of 4-HI while driving. I believe this originated with 1970s/1980s domestic trucks that could shift on the fly with auto hubs, but could not with manual hubs. That's not a problem with Toyota components. As long as the hubs are turned in, I can shift in and out of 4-HI at will while driving.

I was insistent on keeping ABS until I tried it last winter and experienced how ineffective it is on the 1st gen Tacoma. My new steering knuckles don't have this port for the ABS sensors so I removed them. That will cause the ABS warning light to stay on.


Removing the two ABS fuses in the underhood fuse box does not disable the ABS light, so it's time to get into the instrument cluster. The 3rd black knob next to the gray knob holds the ABS warning bulb. Twist it 1/4 turn counter-clockwise and it pops out. Then you can remove the bulb:


Removing the ABS modulator and reworking the brake lines is a project for another day. Also, the green 4WD icon in the instrument cluster no longer illuminates since I removed the ADD actuator and wiring harness.

I will know 4WD is engaged because I'll get out, lock in my manual hubs, shift my manual transfer case into 4WD, put my manual transmission in gear and possibly crank down my manual windows. That will be more manly than John Wayne making out with Donald Trump during a Ford Super Duty commercial on the 4th of July.
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Sorry to revive this thread awesome explanation I only have 1 question. What are you pulling your donor knuckles axles and hubs out of to put in the tacoma?

 

Years ago, I had a 1992 4Runner, w/ADD, a 5-speed m/t, and w/a rare 22R-E 4-cylinder engine in it.
The very best I ever got on the highway w/it, Stock, was 24 mpg.
With ADD, w/no locking hubs, each axle on each side of the vacuum actuator still turns w/the wheels.
I put manual hubs on it, and replumbed the vacuum actuator on the axle to stay closed all the time, to act like a normal solid axle 4WD.
Not only w/the hubs locked and the ADD locked permanent did it shift in and out of 4WD a hell of a lot better and smoother, but w/the hubs disengaged, in 2WD, I gained around 2 mpg for a total of 26 mpg highway, since no portion of the axle was turning anymore.

 

This might help - Go take a look at this steering knuckle.
https://parts.toyota.com/p/Toyota__/Steering-Knuckle-Left/63066616/4320235061.html

Notice "What this fits", click on it and then click on "Show More"



You'll see all the various models you can look at for steering knuckles, or just re-use your own (will require pressing out the ADD hub and swapping in a manual hub along with a new bearing of course). If you do not have ABS and you find a set of steering knuckles with the ABS port, you can plug it with this - https://absolute-wits-end.com/toyota-truck-abs-sensor-delete-plugs-front/

As for non-ADD CV Axles, 1995-1999. They had a blue sticker on them. ADD axles had a green sticker from the factory. Or, just go with aftermarket (problematic though). There are still a few Toyota parts departments out there that have Remanufactured non-ADD CV Axles available. You'll need to search for them and they do have a core charge but if you have access to a couple of junky CVs, I'd go this route over salvaged CVs.

non-ADD hubs, I would just go with OEM. Forget the aftermarket hubs. Too many problem stories floating about the forum with these. OEM for the hubs and bearings. IMO only of course.

non-ADD hub lockouts can be found here (or rebuild a salvaged set) -

$124 AISIN FHT-019 4WD Free Wheel (Locking) Hub - Compatible with Select Toyota Tacoma

https://smile.amazon.com/gp/product/B015R1EF6Q

Cheers, hope this helps answer your question.

 

Hi @DJB1,
Sorry to bother you again with this thread, but since I did the manual hub conversion on my truck I started feeling like a rough/vibration by the floorboard and front end, that I finished replacing many parts trying to find out the problem (Lower Ball Joints, Control Arms Bushings, New Rack and Pinion and Bushings, Tie Rods). Also, I went to different mechanics, but they don’t make an accurate diagnostic and the last one told me that he found some metal residues when he removed the free wheel hub from the passenger side, when I checked it, that metal residues came from the drive axle spacer (Reference Picture Below), something is like pulling the passenger side drive axle or something like that.







Now, going back to the intermediate gear shaft that I asked you before, this gear needs to be removed or I need to leave there as now is? sorry if sounds too repetitive.









My Tacoma has different a style of lever T/M shift, that doesn’t have the ADD button like yours, I don’t know if this make any difference relative to leave or remove the prior intermediate shaft gear.








Sorry for insisting so much on this gear, the thing is this feeling like rough/vibration floorboard that my truck has, feel very similar when the 4wd is engaged, so I don’t know if this gear is the guilty of this problem and I failed when I leave it.



Thanks in advance and sorry for the long text,



Juan

 

Hello Juan,

My truck did not have the 4WD button on the transfer case stick. It was the normal J-shift case, called that because it shifts in and out of 4WD in a "J" pattern. I can't tell from your photo which transfer case you have. That gear sticking out of the front differential is only needed if you're keeping the ADD actuator and intermediate shaft. I removed it from my truck in order to use a donor non-ADD shaft:


As for your truck's symptoms, you said you found metal residue that came from the spacer in your freewheel hub and it feels like 4WD is engaged on that side. To me that sounds like you have a malfunctioning freewheel hub that's not fully releasing from the CV axle when you have it turned to the UNLOCK position.

 

@DJB1 thanks for your reply,
I have plans to uninstall both axle to check if I can see something wrong.
Are you experiencing some floorboard vibration? By the driver rest foot pad close to the firewall, I have this problem by this area and also on the gas pedal.