I have a 1998 4Runner Limited with the push button 4wd.

When I put truck into 4wd, and engage the button, no light comes on the dashboard. I can hear the "click" of the relay, and I can feel the transfer case engage manually. Well I can feel the resistance, and it clearly is moving.

I have been searching the net for days, found many useful threads, and so far this is what I have done to trouble shoot:

When it is in 2wd, the front driveshaft spins freely.

When it is in 4wd (either high or low) the front driveshaft is locked in place.

When I put it in 4wd (either high or low) and jack up a front tire, it spins freely and is NOT locked into place.

So I am guessing the front actuator is working properly, and perhaps the ADD is not locking the differential?

Any and all help would be so greatly appreciated.

 

I am going to check the vacuum lines on the front differential and report back, seems that is important information.

 

Assuming you have an automatic, but you can also check the little vacuum hose between the shifter bases. Lift your center console out and remove the cover plate that covers up the shifter handles from the top. you should see a small, u-shaped vacuum hose between the two.
When I had my transmission replaced, they forgot to hook that back to the 4X4 shifter, and I had the exact same problems you are having.

Hope it helps! Good Luck!

 

That seems simple enough. I am going to check it out. Thanks very much for the reply. I will report back once I check it.