A.D.D. vs Manual Hubs

[Stillrunning]

I'm new to Toyota.I have a 92 4Runner with the auto hubs.My understanding is that they are vacuum actuated.Is this system problematic?Should I switch to manual hubs.I bought the truck to use in the mud and snow.Just want to ask as I want to make my truck as good as it can be.Thanks.

 

[Diverse4runner]

Ive been wondering the same thing but I did this and drove an hour back home with no problems

 

[drewgarrett]

You have ADD hubs, not auto locking hubs. You have a thick metal flange that connects your CV half shafts to the wheel. The CV shafts turn all the time which is nice because you can throw you transfer case lever into 4WD and be ready to rock n roll. There is a coupling in your front axle that locks the shafts together that is vacuum actuated, but you don't ever hear of them failing. There are people that will bypass the vacuum coupling and lock em together with a hose clamp, but the factory setup is very good. You don't have to get out and lock your hubs, just throw your tcase lever and you're ready to go.

 

[4running1990]

I mean it all depends on how much you use 4wd i have manual locking hubs on my 95 with a 90 Toyota pickup diff. and they are really strong. If you are an occasional off roader manual locking hubs is the way to go (unlocked: saves cv's and cv boots no front end drag) if you need 4wd almost every time you drive you can just keep them locked just unlock them on dry firm surfaces. In my opinion the Stock Aisin hubs are the best you can get.

 

[fourwd1]

The Vacuum Switching Valves that lock and unlock the front axle do sometimes fail.
The ADD doesn't use any hubs, it uses drive flanges as described above. You could swap in some manual hubs that would decrease wear and tear on your front end and increase MPG a bit. Or you could get rid of the ADD system altogether by swapping out part of the fron axle.