2nd Gen 4x4 troubles

I would appreciate some thoughts on my 2008 Tacoma 4x4 troubles. I was driving in 4 high and I took it out to go back to 2 high. Then changed my mind as I was back in snow. So I went back to 4high...It did not go into 4x4 high. I have never had a problem with the system and it was a little upsetting. The truck has 186,000. The weird/good thing is that when I turn off the truck and turn the switch to 4 high and then start the truck up it goes into 4high with no problems. It also goes out of 4 high to 2 high with no problems. Any thoughts about my gremlins?

 

Check the vent hoses on the actuators first, if one is disconnected or missing then the actuator likely has water in it. If those are good check your limit switch voltages as outlined in the thread below and we'll see what's going on.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

How hard did you try? I've had to stop and go, put it in reverse, etc for mine to click sometimes. When I first bought my truck it refused to go into 4x4 and we had to replace some part of the ADD. I've also heard mention of a mod where you wrap a thick copper wire around something to give it better connection, relieves symptoms of 4x4 not wanting to change modes.

 

I wouldn't mind more details on the copper wire mod. Mine was stuck in 4hi the other day, but the problem went away and hasn't reappeared after I turned the truck off and back on.

 

Yes, the vent hose is the Achille's Heel of our 4WD system.
Listen to @Dm93 he knows his stuff.
If you haven't used 4WD for a while, sometimes a little exercising (switching in and out while driving straight or on a low traction surface) can get everything working again.

Check the vent tube and report back, please.

 

Another tip is to cycle the system in the driveway back and forth with the switch from 2H and 4L and back a few times and see if that improves things. This helps to wipe/clean the contacts in actuator(s). Another good practice is to run it in 4H on a rainy or snowy day for a mile or two. And as others have advised, inspect the vent hoses, especially for cracks at the ends where they connect.

 

https://www.tacomaworld.com/threads/a-d-d-issues.491333/#post-15148099

I couldn't find it, but if I remember correctly someone's fix had to do with Post #6 in the linked thread about pressed contacts coming loose