theitguy

Hey folks Happy New Year!

I have been a reader for about 3 yrs now, first time poster.

I have a 92 4runner SR5 V6 3.slow 4x4 with Warn manual lock hubs. Bought the rig as is about 3 years ago and have not had any problems I couldn't resolve with the help of the great posts in this site until now.

The other night my father in law called me up and was stuck in the mud, I went out to help him and without hesitation threw the old girl in 4x4 and went in after him. After getting my truck stuck as well I noticed no 4x4 light and he noticed only 1 rear wheel spinning when giving it gas. No other wheels turning. Yes the hubs were in lock position.

The truck runs fine in H2 and last winter being the last time I was in 4x4 it functioned correctly and light was lit.

I have scoured this site for hours on end and even after looking at posted pics etc I can not determine if the truck has ADD ( I thinks I do at this point though).

I just came in from having another look, with truck running I had my wife throw it in H4 and pull forward a few feet. The front drive shaft is turning, same result in reverse and also in L4 yet no 4x4 light. When switching from H2 to H4 or L4 I can hear the click from under the dash that most every other poster with this issues has described. When going from H2 to H4 or L4 there are no horrendous sounds nor have I heard anything blow up or had any symptoms or indication that anything was wrong.

Other than getting back under it and determining if it is ADD which I plan on doing tomorrow is there any advice/suggestions you guys have for me.

Thanks for listening and for any advice you can share.

Sorry forgot to mention that I am a weekend warrior mechanic at best and this is my first 4x4 vehicle so be gentle.

wyoming9

iTrader: (1)

Do you have a automatic or manual trans?

If you look in from the front of the truck if this is the add system that someone put Locking Hubs on Like I did to mine

You will see the extra valve bolted to the front differential .

If it is ADD they have a habit of not working if not used for long periods of time.

wyoming9

iTrader: (1)

If it is indeed the Add system They don`t like to be left unused for so long!!

I put hubs on mine I engage the ADD at least once a month.

Do you have the manual or Auto Trans

I have the same year 4Runner with a 3.4

If your close I would be glad to help.

Yotard

Easiest way to know if you have add is to take the skid plate off and if you look at the front diff you will see an electrical connector and two vacuum hoses that attach to the add actuator on the axle tube right next to the differential itself. Those vacuum hoses can go bad sometimes or the vacuum switching valve goes bad. The electrical connector is the sensor for your dash light to tell you it is in 4x4. Switch the two vacuum hoses and see if the light for 4x4.

theitguy

Hey guys thanks for the quick replies, sorry for leaving out the tranny info...it is automatic.

As for being close its looking like about 2.5 to 3 hrs away wyoming9. Im in pine bush, ny.

Thanks yotard, I will take off the skid plate tomorrow and have a look. I'll try an stake pics as well.

I appreciate the help.

theitguy

Wyoming9 I have been throwing the idea around in my head to put a 3.4 in it...then again I've also been thinking of putting a V8 in it but the research I have done on that seems like too much work when from what i've read the 3.4 will drop right in.

wyoming9

iTrader: (1)

A little more work then drop right in.

but fitting it in the engine compartment is the easy part.

Your pretty close on the time most times I can get to Middletown in about 3 hours

theitguy

Having a bad day with the truck today. Tail gate window got stuck half way down and won't go either way. Had to replace that motor when I bought the truck and haven't had an issue since. But that will have to wait.

I'm hoping this pic is of the ADD:

And I'm guessing the other end of vac lines are somewhere in this mess.


Let me know if this is what I need to deal with...thanks wyoming9.

theitguy

OK, any ideas why image won't display?

Never mind got it.

wyoming9

iTrader: (1)

That is the ADD system most often there is a vacuum tank floating around someplace

the VSV (vacuum switching valve) looks to be right behind the fuse block on the right side. of the engine compartment.

There is also a relay up in the dash to the left above the ebrake handle

this circuit gets power through the 10 amp gauge fuse if that is open it will not work.

The relay powers the VSV which allows the vacuum to move the lever on the axle this is the simple version.

Then you don`t know if the Add system has worked since you bought the 4Runner Since the Hubs were installed the axle can be made to be left in the connected position .

theitguy

It is true that I do not know if the ADD system ever worked, however I do know for a fact that the 4 wheel drive system worked and was used up until probably April of 2014.

I will check the fuses to start, not much else I can do today we got about 3-4 inches of snow now and rain coming tonight and tomorrow.

I appreciate you taking the time to share your knowledge.

theitguy

I read in other posts that ATF level can make a difference as well and noticed mine was a little low but not empty. In your opinion could that be a factor. I am going to get out this evening or in the morning and I will pick some up and add just in case.

theitguy

On a positive note I got the tail gate window closed before the snow started falling.

theitguy

Gauge fuse is good.

Will keep digging into it tomorrow.

Thanks again for your wisdom.

wyoming9

iTrader: (1)

Not a big Auto trans person I don`t own any.

Yotard

Down at the diff unplug the vacuum lines and swap them this should engage 4x4. The vacuum is constant when the engine is running it either keeps the diff in 4x4 or pulls it out of 4x4 by swapping the hoses you should be able to put the vacuum line that keeps it out of 4x4 to put it into 4x4. If this does the trick then you know that your diff and the add system works and that it is somewhere is the vacuum switching valve or hoses or the electrical system that switches the valve.

wyoming9

iTrader: (1)

If you search using your search engine of choice Toyota ADD delete it should give you lots of information on just how the system works.

Not having these vehicles from when they were born does make it hard to figure out what the last owners might have messed up.

theitguy

I will look into these recommendations today.

Wyoming9 if as you mentioned the previous owner that installed the manual hubs set it up so that the axle was made to stay in the connected position what might I look for to determine that?

Again many thanks to you both for sharing your wisdom.

wyoming9

iTrader: (1)

If the front has been moved to be in the locked position all the time.

With the hubs unlocked both cv axles will spin.When you turn the front drive shaft.

With the hubs locked both wheels on ground the front drive shaft should not move.

Then it could be the means the last owner used to secure it has failed.

Thing is without really knowing you need to pretty much trouble shoot the entire system.

It is not that complicated but the first time can be interesting

theitguy

Sorry guys no update on status yet. Due to rain/snow/ice and sub freezing temps I haven't climbed back under the truck to continue investigating. Hopefully by this weekend I'll have gotten further. Was going to try today but got more snow, and it was 10 degrees when I got done working. With the 30 mile an hour wind gusts wind chill factor was a -15.

Thanks so much again for the info though, I'll keep you posted.