1990 4runner SR5 3VZE Automatic.
For some odd reason my front axle is not locking in. The transfer case locks in...definetly,but the front axle is def. not. The little idiot 4x4 dash light isnt coming on either.
What locks the front axle? An electrical switch of some kind?
I've replaced the driver side half shaft in the 10yrs that I've on this 4runner and 4 wheel drive always worked fine. Last winter,about half way through the winter,the front axle stopped locking in. Winter is slowly creeping up on me and I'd like to get it working.
Any help?
I've read the manual and can't make heads or tails of it as they describe so mnay different types. I have a high school auto mechanics schooling,so Im not completely un wrenchable

 

I might be wrong but aren't those vacuum actuated? Might have had a hose come off?

 

Good place to start troubleshooting...thanx.

 

probably the actuator

 

check the small vac lines on the actuator itself, easiest ones to check they arent 4-5 inches long just make sure their not ruptured

Next check the long lines from the vsv to the actuator, the vsv is located on the passenger side firewall behind the fuse box. If you take the skid plate off you can trace these lines to clips on the frame and up to the vsv.

I had an issue with these lines specifically, the lines came out of the clips and were too close to the engine heat, melted and lost vaccum therefor not applying vaccum to my actuator.

Next check your vaccum at the vsv simply pull the lines off and check for suction.

Or you could work it completely backwards and start at the vsv and go from there.

I'm currently looking for manual hubs so i dont have to deal with this crap anymore, worth looking into.

Pics for what I speak of, great thread with pics
https://www.yotatech.com/forums/f116...gaging-196187/

 

not trying to hijack but i'm still looking for the mystery vac line that goes here that I found when I was working on my ADD, any ideas?

The pic shows 2 fittings right behind the fuse box on the passenger side between the it and the vsv, I've got the one line from the vsv hooked here on the bottom and currently nothing on the top.