im helping my friend who has a 93 toyota 4x4 with ADD. his 4wd isnt working, and we checked all the solenoids and relay and it seems to be working fine. i think the vacuum for the ADD isnt working so can i just convert to manual hubs to fix this problem? or do i need to change the whole spindle and hub assembly rather than taking the ADD flange off and bolting on the aisin manual hubs?

 

I originally just changed the hubs and everything worked great.

Later, I found a guy that had a complete front axle for nothing that was non-ADD so i ended up swapping out the axle tube as well thus getting rid of the actuator

 

I disconnected the vacuum line and locked the fork to the side.. and changed the hubs. it was actually really easy.

 

Changing the hubs does nothing to fix the problem with the ADD system.

The drive flange locked the axle to the hub, so it is always spinning. The way to fix it is A. replace the ADD jack shaft and axle tube with a non-ADD jackshaft/housing or B. Fix the ADD problem, whether its the solenoids, lines, or actuator on the diff.

 

on my 91 runner i locked the actuator in place and put on a set of asin hubs on the bottom od the add unit there is a bolt with a spring behind it its a detent for the fork i just put the fork in the 4x4 engage position and replaced the bolt and spring with a longer bolt holding it in the 4x4 position at all times and it worked great

 

Ya, i should modify my post. Originally when i changed my hubs, I locked the actuator in place as well and then disconnected the vacuum lines

 

ok. so i have to fix the add first before i put the manual hubs on. i used the search button and read a bunch of other posts that says you can slap on the manual hubs and everything on the ADD will be non existent. thank you for clearing that up for me. how do i lock the fork to the side? is there a write up somewhere?

 

Think of it like this. There are three links to making your 4x4 work: transfer case, add actuator, hubs. All have to be engaged to work.

If you just throw on hubs without the actuator locking things in place, then nothing is happening cause the actuator is stuck open. I'd be the same as leaving the transfer in neutral and locking the hubs thinking you were in 4x4.

 

hey. i want to go from add to manual locking hubs. so besides putting on the new hubs... there's more to do? vacuum lines? and locking the actuator in place? how does a person do that?
oh ya it's a 1992 4runner 4cyl. thanks

 

http://www.off-road.com/trucks4x4/ar....jsp?id=399612

Down near the bottom.

 

http://www.4x4wire.com/toyota/tech/add/

Or you can just run a vacuum line directly from the intake to the engage fitting on the actuator.

 

ill try it out...thanks for all the help guys! ill keep it posted on how things go!

 

i rigged my ADD IFS diff with a hose clamp - seems to have worked pretty well. take off the cover of the ADD actuator, slide the gear over to engage it, then slip the hose clamp around the shaft and clamp it on. Its a tight fit for a hose clamp (I had to trim a tad off mine with snips) but it did fit eventually. The hose clamp will act as a wedge that will keep the gear engaged all the time.

 

i was trying to figure out how to make the fork stay in place just a few minutes ago... ill try the hose clamp. thanks!

 

biggest reason to swap out the entire axle tube with all the stuff, is that the inner axle is MUCH stronger than the ADD axle...

the ADD axle actually tapers in, and get smaller. so when you're locked (or at least with a tru-trac up front), driving in 4 lo-lo (with a marlin dual crawl box) and your front tires get up in the air; when you land, that front axle wont spin and shear off so easily...

lol...

the swap is easy. besides the whole non ADD axle tube and axle assembly, you need a seal for the front diff when you bolt (and i do mean bolt) everything back together...

 

I have reason to believe that this has happened to you, lol.

 

this is all confusing me lol. as far as i always new you just swap the hubs for manuals and thats it? no add actuater stuff just put your t case in 4wd and lock the hubs and you have 4wd right? take the t case out of 4wd and no 4wd or unlock the hubs and have no 4wd lol. add hubs are just a plate bolting the cv shaft to the hub lol

 

The OP's issue is that the 4x4 isn't functioning - the ADD isn't locking into 4wd, so the acctuator fork need to be engaged to lock the shafts together.

All the manual hubs do is lock the hubs to the shafts.

All that adding manual hubs to a functioning ADD system does is retain the shift on the fly function (while the hubs are locked) that and give you the ability to shift into 2low (with hubs unlocked)

 

yeah thats what i thought haha. thanks for clearing that up 91 4runner.

 

dang guys..ya'll had me a lil scared there for a min LMAO!!!

i still think i'll swap out the whole ADD tube though if i get the chance just to get rid of the weight..and get a little strength back lol