ok, so im out at my family ranch over the weekend, and I go to play in the river and bam, stuck and no 4WD.... what are some possible problems associated with 4wd not engaging. No light or anything... im confused
please help

 

bump.....

 

Check all your vacuum lines. I'd be willing to bet that's the problem. When a vacuum line breaks going to the ADD mechanism, it won't work. I think there are some lines that run to the 4wd selenoids and then down to your front diff.

Good Luck

 

I've had this problem a few times, and tracked it down to the vacuum canister inlets getting clogged with crap.

Dunno if your truck is the same as mine. But my canister is located in the passenger side wheel well by the front bumper (From the tire or outside the truck). You have to remove a plastic mud flap to access it. Remove the 2 vacuum hoses and try and push a small drill bit er something threw the holes.

If inlet and outet are not plugged you have to start tracing the vacuum lines from there.

BTW my truck is a 91.

 

where are the vacuum lines on a 96 4runner... also where are the 4wd solenoids and where is the ADD mechanism.... its bothering me alot

 

http://www.off-road.com/toyota/tech/add/index.htm
A few other have had these problems so there should several threads on it. I just can't find one with a picture. Try searching though