2002 4runner won't shift into 4x4

[Sluggy]

2002 4runner 3.4 auto sr5, has the 4wd button on the shifter.

I was hoping someone can help point me in the right direction on my cousins 4runner. Truck won't go into 4x4 and the 4x4 light on the dash won't stop blinking. Tried to reset with scanner and rocking it back and forth but no luck. Anyone else run into this or can help with some insight?

 

[Chkn]

Without looking at it my guess is the ADD on the front axle.

 

[McAustin]

My guess would be the limit/stop switches on the transfer case or possibly the ADD. These switches will indicate when the shift collars and such have moved into the correct position. Without seeing that it will not shift properly. The e-locker diffs use something similar for the computer to lock and unlock the diff properly.

 

[rockota]

My guess would be the limit/stop switches on the transfer case or possibly the ADD. These switches will indicate when the shift collars and such have moved into the correct position. Without seeing that it will not shift properly. The e-locker diffs use something similar for the computer to lock and unlock the diff properly.

This...

the tcase is very sensitive on mine... for engaging and disengaging.

Throw it on jack stands (all 4) and see if it'll engage?

 

[Sluggy]

It doesn't chirp when driving in 4x4 on the street hard locked. I'm gonna put it on a rack in a couple hours. Thanks for the heads up guys

 

[rockota]

It doesn't chirp when driving in 4x4 on the street hard locked. I'm gonna put it on a rack in a couple hours. Thanks for the heads up guys

Is there a button to the left of the column that looks like the dash indicator (4 tires) with an “X” in the middle?

If so, it has the multi-mode tcase that gives AWD via the tcase button… and that button locks the tcase to give 4wd.

 

[Sluggy]

So after some investigating, I found the vacuum line that goes to the tcase actuator was cracked. I cut the cracked part off and put it back on with no change. I then tested the 2 switches that are right next to it. The rear one is not showing any ohms when exercising it off the tcase. I ordered a new one from toyota 30 minutes ago and it should be here tomorrow.

I haven't had time to look at the front diff yet but I did notice that the front driveline is locked in at the moment. So maybe I'll need to check all the vacuum that goes to that.

Rockota, is this the switch your taking about? I've pressed it but it did nothing.

Thanks again guys for the help.

 

[rockota]

That’s the switch.. it locks the center diff in the transfer case. That’s why you don’t feel any binding on pavement - the tcase engages but only AWD… until that button is pressed.


Edit: would be curious if it’ll engage/disengage on Jack stands. Mostly because mine is slow AF

 

[Sluggy]

Quick update on the fix, ended up being the rear sensor on the t case that was causing the issue. I thought it was stuck in 4wd but it was in 2wd and the front was locked in. Once the sensor was replaced it shifted just like it was supposed to. Here are the pics of the sensor and is location.

Fyi buddy at toyota said that you can remove the aluminum washer and it will get ya by till you can replace it.

 

[buzzbombxj]

I have a 2000, but it's multimode so same tcase, mine would occasionally do the same thing, and also occasionally put itself from 4x4 to awd on its own. Turned out it was the shift motor in the tcase.