4 Wheel Drive Not Working Blinking Light.

Hello,
Last week I switched my 4 wheel drive in while moving my truck in gravel. It had the clunk but more loud than usual. Later when I got in my truck I turned it out and it your not disengage but then did and light blinked continuously. After driving it I had my Father while visiting home turn the ignition on and off while under the truck. It engaged and disengaged. Upon research I took the the ADD off and it was clean and with 12 volts the motor ran by touching the outer motor tabs. Tested the limiter switch for continuity which was positive. The slip lock color was engaged so I did move it and match the motor position and switch to match so it is open now. ADD was clean inside.
Moved to the transfer actuator position sensors and they are free and everything is clean. Decided to pay 50 dollars at the Toyota dealership to test. They ran the test sequence tested both actuators. Their write up says and talked to the tech to confirm "Inspected 4 wheel drive system due to light flashing vehicle is not in 4wd at front diff and tcase are both unlocked. Checked Tcase shaft position switches they are working as designed. The transfer case motor position switch is not working as designed causing light to blink. Correction new tcase actuator." enjoyed their broken english.. So not convinced I pulled the tcase actuator cover off everything looked good. Still no 4WD and light blinks when selecting from 2h-4h-4low. Went as far to pull the large plastic gear and back plate to operate the actuator rod by hand. Put all back together still not working. And yes marked the position to put it back in the correct spline and position.
If the switch motor is bad on the tcase why does it operate when your cycle the ignition switch on and off? And does lock and unlock the transfer case and front drive shaft. Also the ECU is clicking and checked all connection front and back. Could the Toyota Tech be right and it is something I do not see? Also they said they do not break open the actuators and you have to remove by splitting the tcase. that is not right. You can remove it by taking the small gear out behind the inspection plate. any ideas before I by a used tcase and put it in?
Thanks!
Could write more but my fingers are tired.
my second toyota tacoma and more problems.

 

There's a few threads on this. Check out the search.

 

Thanks. I have looked at read every thread I read many times over. They all point to ADD and some says who has my exact symptoms it just started working again. I wonder is the shift rail is not sliding fully but enough to lock the front drive shaft. If I understand the sequence right it goes switch 4h - ecu-tcase once ingaged - ecu - add once engaged light off. Then neutral 4l and so on. Dunno guess I am frustrated. No real explanations on other threads on why cycling of ignition works the actuator. I am thinking a voltage surge is making the tcase actuator run. Plus little talk on the Tcase Actuator just swap to a fj which is more work than I want to do for a daily / weekend mountain truck. My trouble shooting is at wits end. Here I thought I was reasonably good at fixing trucks considering I can rebuild a engine bottom up. Damn Toyota and this 4wd system. I agree Manuel TCASE and locking hubs on a solid axle. oh and before this happened I just put in the ECGS bushing. What a sloppy bearing set they put in off the line.

 

Any Toyota Techs on here have input?