jay4runner

The 4WD on my 1990 4Runner has stopped working (as has the 4WD indicator light on the dash). I have been advised that it is my 4WD switch within the transfer case that needs replacement. Can anyone tell me what this part is (I would like to find it and price it out). And, whether this diagnosis makes sense. Thank you.

gyoas759

Need a little more info on this. Is it a manual or automatic transmission and what engine? Is the shifter for the transfer case still moving properly?

The switch could explain the lack of the indicator light but wouldn't prevent the transfer case from engaging if it's shifting properly.

Birdbrain

Gyoas. your mostly incorrect


The ADD in the 2nd gen 4runners is activated by the switch in the transfercase that also operates in dash light. although the actual case might be in 4wd and the driveshaft spinning, the vacuum actuator (which allows the power to go to CV's) is activated via a solenoid activated via the switch (on the transfercase IE dash light switch) when the transfercase is moved into the 4wd location. Thus, if his switch is bad he would have no 4wd.

I found this out the hardway when i did my 5speed swap, being ignorant i decided to not wire reverse lights (meh, my tire swingout covers those anyways ) and my 4wd indicator. At the time i thought thats what it did. indicated the 4wd light. Little did i know when i went for a light wheeling trip and got stuck.... and no 4wd (its amazing the placebo affect i had before i ACTUALLY got stuck) that the switch (that i had no way of connecting...) activated the solenoid. Using jason for help (THANKS MAN!!!!) we jurryrigged a vacuum line swap to permanently pull the actuator over while my engine is running. The only downside is while my hubs are locked my diff/driveline should theoretically spin outside of 4wd.

Now this fix worked for a 5speed... not sure of the automatic.

If you have manual hubs you can do what i did and just ignore the light. to this day my switch is still not hooked up. (not sure where the write up is offhand. do a search)

OP; do you have manual hubs?
Auto or manaul? I might have a switch laying around... take pics of your old one please and ill take a look tomorrow after work.

Cheers

jay4runner

It is a 5 spd manual transmission. The shifter works ok. Also, when put into 4WD(Low) it is geared down very low. But, the 4WD isn't actually working (at least not in high). I just had my clutch replaced and it was immed after I happened to notice the 4WD wasn't working. I took back to the mechanic that replaced my clutch asking if the work they did maybe caused the 4WD to stop working. He claims not and says I need a new 4WD switch (which he says is in the transfer case). I just wanted to be able to price out this switch on my own.

scope103

As far as I can tell, there are two switches:
222-35060 SWITCH, TRANSFER INDICATOR, NO.1
222-35070 SWITCH, TRANSFER INDICATOR, NO.3
I believe one is to detect 4wd (which would drive the front differential ADD), and the other is to detect L4 (4wd low) for the benefit of an automatic transmission. I can't tell you which part number is which.

For diagnosis, you might try jacking up one front wheel. With the engine running (you need vacuum) and the transfer case in 4wd, try turning the wheel. If it turns, it means the ADD didn't engage, which could be due to the switch. (or vacuum, etc.)

Good luck.

Birdbrain

Jay,

Although you may be shifting your lever into 'low' your transfercase will reduce your gearing. but that power is ONLY going to your rear wheels. Until you replace your switch, you will lack 4wd due to the switch not activating the solenoid for your front differential's ADD.

REDYOTA

Please check your vaccum lines to and from your vcv and actuator ninth percent of the time this is the problem

REDYOTA

Please check your vaccum lines to and from your vcv and actuator ninty percent of the time this is the problem

91Toy4R

When I bought my '91 5speed, I discovered I had the same problem. When I checked, all the vsv's were working within spec but no vacuum to the actuator. But in my case I decided to install manual locking hubs, I just didn't want to fix the problem and have it reoccur at a later date when I really needed 4wd. My 2 cents- install a pair of warns of mile markers. You wouldn't have to worry about the vacuum system again.

REDYOTA

Good advice I just wanted to throw that out before home slice gutted his tcase for a cracked vaccum line to the actuater

jsharpe

i just installed manual hubs on my 90' 4runner v6 5 speed because the 4x4 wasnt working. It still isnt working with the new hubs even though when i shift into 4 low the ratio is right and when i had it jacked up and hubs in the locked position the cv joints were spinning and when in the free position the cv were not spinning.

any help would be appreciated

scope103

Your ADD (in the front differential) is not engaging. Installing manual hubs on only gave you a second place to disconnect the drive.

Does your 4wd light illuminate when you shift into 4HI? Probably not (it indicates a successful ADD engagement). The "most" likely cause is that you have one or both of the vacuum lines to the ADD disconnected. There are only two to the differential area; make sure they are connected and have vacuum when in 4hi.

justin_4runner

on the auto tranny i have when i put it in 4wd i here a relay in the dash area click, now if hes not hearing that relay it would tell me its the position sensor gone bad, if u are and still not going in then i would look at the vacuum relay on the side of the fire wall for vacuum there, then to the front actuator for vacuum.

jsharpe

my lights work in the dash i dont hear the clicking like i used to. and as far as the hoses go i have the 4wd hose and a 2wd hose and i have always just left the 4wd hose hooked up and the 2wd hose just hanging open and havent had any problems before

justin_4runner

by having the hose open dont u then have a vacuum leak?? i would test the switch at the transfer case and if thats good then go to the relay under dash by steering column..

91Toy4R

To jsharpe, if you check elsewhere on this site (search ADD), you'll see an easy way to permanently lock your axle shafts which will enable you to have 4wd whenever you lock your hubs. Check link below.
https://www.yotatech.com/forums/f129...er-mod-200971/
I used this info when I did mine. http://www.facebook.com/photo.php?fb...0663.524069814

jsharpe

thanks 91 toy4r im pretty sure thats my problem now just have to find the time to tear it apart and do it lol

southernsweetieal

ok, im kinda new to this website and because of that it wont let me post my own thread, but yall sound pretty knowledgable on this truck. So maybe yall can help me. I got a 1990 V6 4x4 3vz 4 runner. Just redid the heads, got it all back together after replacing several dry rotted hoses and wires. took it for test drive and some how a wire (that i didnt have to mess with) got wrapped or tangled some how with my steering and got ripped out. Im trying to figure out what it goes to. Truck still runs, I cant see where it got pulled from. Looks like it may be a ground for somthing. it has 3 ends on it one for a terminal type connector and two with pin connectors, ecept it looks like one pin got ripped from the wire. Any ideas would be much appreciated.

justin_4runner

take a pic of it and it will let u post your own thred. go to the elertical section and above the threds it says start new thred, hit that and u can. but sounds like the one that runs down to the diff and oil sending unit, but post a pic and we can tell u more.

southernsweetieal

thanks but it is telling me that if i have less than 15 posts, i will not be able to start a new thread.