Going over a mountain pass, it was snowing pretty good, so I clicked on AWD, at 60mph. According to the internet, I should have been ok up to 60 or 62 mph. Upon clicking, a beep went off for several seconds as I slowed down, and clicked unlocked 4x4 off. After the slowing and turning AWD off, the beeper stopped. The 4x4 light has been flashing ever since.

Later I realized that whether I selected 2wd, awd, or 4hi "locked", it would only ever be in 4hi locked, with the light flashing.

Only a few miles from our destination, we drove maybe a hundred miles over the next three days on dirt in (attempted) 2wd, (attempted) awd, 4hi and 4low. Other then the problem described above, other tcase operation works fine, powering front and rear, shifting from low to high, all good.

We drove up, and down, hills, at various speeds, clicking the 4x4 button, with no changes.

Once home, I unplugged the two rear tcase plugs one at a time, rolled the 4runner forward, drove a few feet, plugged them back in. No change. One of those plugs, once unplugged should put the tcase in neutral, but did not in this case.

Tcase shifter actuator assembly Is about 2,000 miles, 4 months old. Installed by dealer.

Any advice on this?

Wow! I'd never try initiating 4wd at 60, wow.

Have you tried what it says to do when 4x4 won't actuate? Its on driver visor.

I always actuate at under 10mph, way back when I first got it and PO never used 4wd, i learned to turn wheels (at under 10mph) to right or left and 'click' it would go in.

This always has worked for me, sorry I can't be of more help.

Now when you say locked, on multimode those are two separate actions and buttons. Have you tried unlocking first? Then try the 2/4 shifter button to disengage awd, perhaps by going slowly and turning slightly?

After this, I'd take it back to source that can test components to find the culprit. Luck.

Which position was the transfer lever at when you experienced your issues?

What MY is your 4Runner? 1999-2000, the center diff switch is automatically engaged/disengaged by the transfer lever. 2001-2002, the center diff switch is separate from the transfer lever.

it is possible that the 4WD sensor on the front diff is kaput. try checking that sensor.

here are links to some threads that may help you:

4WD won't disengage on 99 4Runner LTD - YotaTech Forums

99 toyota 4runner transfer case problem - YotaTech Forums

Symptoms are like the ADD actuator on the front axle is partially stuck. lift the front end off the ground and tap the actuator gently then disengage see if it works.

Is there any position where the 4wd indicator lights aren't flashing?

My bad, the vehicle is a 2000 limited.

Yes, I tried that at the first big pull out we found. The weathered paper on the visor says either you can drive it at speeds up to 60, or shift it at speeds up to 60, altogether unclear to me. I had thought I had seen on this forum that on-the-fly shifting could be done up to 55, 60, or 62 mph

I am glad you posted this, because I don't think I have tried to do this while turning significantly, which is dumb because that is the key to getting the rear diff to lock/unlock.

This is the crazy thing, I hit the button that puts it into the AWD mode, but, it went all the way into 4hi, which makes zero sense. I am trying to fix it by monkeying with the 2/4 button, cause that is what I hit before, but the lever is what is supposed to lock/unlock, unless I am mistaken.

The transfer case lever was in the all the way forward position when I caused the issue. The light flashing, and being stuck in 4x4 has not stopped since.

It is a 2000. Thank you for these links, I am reading through these threads.

I guess I can't say for sure that there is no problems with the ADD actuator, I can say for sure though that the tcase is in locked 4x4, regardless of lever position. It behaves exactly as a conventional 4x4 does on pavement.

When the lever moves, or button is pressed, the indicator light will stop flashing just long enough to give me hope.


Everyone, thank you for the help on this. I work second shift tomorrow so I have a lot of time to mess with it. If I figure anything out I will come back with results.

More info, the reason the tcase actuator was replaced 4 months ago was because the tcase would only go into 2wd or AWD. When the tcase lever was in the shifted into locked positions, it would only be AWD. It had started to do that intermittently a couple years ago. The new actuator fixed this, and I got one whole 4 day trip out of it before I screwed it up again.

You're not stuck in 4x4. The lights flashing means it hasn't locked. There's 3 external switches in the system that determine positions. 2 on the case, one on the front diff. One of them is bad. Put the lever in 2WD and unplug the battery for awhile. OR try unplugging the 4wd computer. Bottom left kick panel if you didn't know already. That should get the light to stop flashing. Then you have to figure out which switch.


ETA: re read 1st post. I'd put money on the diff switch being the culprit.

I've actually been trying to diagnose the same symptoms he is describing on my 2000 Limited for a couple of months. If the lights are flashing it means that the system hasn't engaged/ disengaged whatever mode you have put it in. I believe it does that after 3 seconds. Assuming his symptoms are the same as mine, when I push the 4WD button to go into H4 unlocked, the lights flash and I am in H4L. I can tell by the drive train binding when I turn the wheel. In my case, I suspect an issue with the A.D.D. system, possibly a vacuum leak. In my case, it will eventually revert to H2 after turning the car off, but not necessarily the first time I do so.

This condition existed on my 2000 Limited a while back.
The switches referenced above were the cause of the problem. Apparently, if not put into 4wd periodically, these switches have a tendency to stick.
I removed them, and worked the spring loaded switch ball in and out with some lubricant. After putting them back in, problem went away immediately and hasn’t returned for I put the system they 4wd and multimode more regularly now.
Give this a try. My switches were still good, just stuck not making good contact. Cost was nothing but time to pull and work the switches.
Good luck.

I went through this shortly after buying my 4Runner a few years ago. I removed all the 4wd sensor/switches and cleaned with contact cleaner and made sure the continuity was good when depressed, then I verified the transfer case actuator was operating by applying power and ground to the actuator forcing the motor to cycle from 2wd all the way to 4hi locked, then I applied vacuum to the add actuator and verified operation, then I verified the vacuum switching valves were operating correctly. My problem ended up being a bad vacuum line to the vsv assembly.

Edit: Flashing lights mean the system doesn't detect the sensors are reporting the locations that the computer expects to see for the selected transfer case position. It doesn't necessarily mean you are stuck in 2wd or 4hi or 4hi locked or whatever position you were before you changed transfer case selections. In my case the add never engaged but the transfer case stayed in 4hi.