richdavies

1999 4Runner Limited V6 ADD. Posted a few other problems you have helped me with or found posts to help me. This is my first Toyota anything. Reading all the posts I can't figure out one last problem. I bought it as a non-running 4Runner from a third party not owner so I have no history on it.

The 4WD works great goes in and out perfect, except when I use the ADD (if my terminology is right) or the button on the 4WD select lever not sure what of the right terminology. I push the button on the 4wd select lever and it goes into 4WD. Then it won't come out. I can manual jumper the actuator back into 2WD and everything works perfect again, 4WD high works, 4WD low works, 2WD works back and forth no problem, as long as I don't use the ADD.

I have checked every switch, sensor and vacuum and everything appears to function properly. I must be missing something!

So right no I just unplugged the switch so I don't accidentally hit it but I would like to have it working right.

Thanks again for all the posts.

TheDurk

Yeah, you got the terminology confused. ADD is Automatically Disconnecting Differential, and is what differentiates our system from manual hubs. Anytime you engage 4wd, no matter how, you are using ADD. When engaged, it locks the front driveshaft to the stub axles, allowing front-wheel drive. Not engaged, the front wheels are independent and undriven. Did you mean AWD (All Wheel Drive)? That is 4wd with the unlocked center diff that is engaged just with the button?

richdavies

You might call it AWD. My understanding is that the Limited has a button option (I will call it the "Look mom I have 4 wheel drive button"). For some reason you can push that button and it will engage the 4wd or you can pull the lever back a couple inches and do the same thing. Maybe it is an AWD variant I'm not real sure what it's purpose is.

I thought I screwed up the ADD thing term, oops!

Thanks

MudHippy

He just told you. The difference is 4WD(center diff locked) or AWD(center diff unlocked). So you should call it the "Look mom I have fake/Subaru Outback 4WD button".

richdavies

Hmm, I see I didn't realize that's how that worked. No owners manual. Any idea why it won't disengage?

KZN185W

iTrader: (1)

there are instances wherein the 4WD button doesn't engage/disengage immediately. sometimes it will engage/disengage only after rolling for a few seconds.

and yes, the 4WD button on a 1999 Limited is actually AWD, which is 4WD but the center diff is open or unlocked.

Malcolm99

Sounds like the positions on the ADD motor/sensor maybe out of faze, and KZN has it spot on, push button 4wd = AWD = all four tires are solid green, shift to 4H(L) = 4x4 centre diff locked and the orange pumpkin shows up and all 4 tires are solid green. 2wd no illumination. My 99 has 120,000mi now and full synthetic gear oils and it usually takes a 10-20ft roll to engage/disengage.

richdavies

OK I will look at that....Thanks

Malcolm99

Read through this, it might give you a few possibilities. https://www.tacomaworld.com/threads/...tuator.263525/