I have a 92 4runner with ADD, and the front drive does not engage when the truck is in 4-low or 4-high.

I jacked up the truck, all for wheels off the ground, started it up and found that the the transfer case sends drive to the front drive line [the front drive line spins] but the front differential does not transfer the power to the front CV joints or the front wheels.

Should I replace the front differential box, or could it be a vacum or electrical problem with the ADD?

Should I just take it to the dealer and have them Diagnose it?

I have a Chiltons manual for the car but it does not seem to have any useful information about the ADD system on this 4runner...

Thanks in advance for any help!!!!!!!

 

check the vacuum lines and any electrical lines that are connected to the front diff..............more often than not its just a vacuum line thats leaking (easy fix)

 

You could always get some manual hubs and do this: http://www.4x4wire.com/toyota/tech/add/
If you don't want to dump money into getting it working.
I personally want to find a non add axle tube and get rid of that crap with manual hubs you don't need add.

 

You didn't mention if the 4wd light comes on or not. If you put vacuum on the ADD port closest to the diff it should activate the diff.

 

I will check the electrical and vacum systems.

The 4wd Light on the dash does NOT turn on, so maybe that is an indication.

Hope it is just something simple...

Other wise I have a set of manual hubs and I guess I will covert it, cause I need a cheap fix.

THANKS!!!