Tacoma 2010 4WD Not engaging

Hi Everyone,

My Tacoma’s 4WD refuses to engage. I have the green H4 light that’s blinking constantly. No 4LO light illumination. Initially I would hear the relay on the 4WD ECU chatter a bit when changing the position of the selector switch but now, nothing. What steps should I take to diagnose or is there a specific component failure that results in this?

 

Check your limit switch voltages as outlined in the thread below and post them then we can see where we need to look.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Some good information, including basic operation overview and trouble shooting here:

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Guys, Thanks for the responses! Extremely helpful! I did some “digging” and found the attached. I think it’s safe to say this one is not recoverable and needs to be replaced.
2 additional questions.
Firstly, is it possible to move the rod by hand to the 2H position? I think mine is in 4H (when I rock the rear drive shaft, the forward shaft rocks as well). Secondly, I hear a buzz coming from the locking motor on the front diff. In bursts as if the system is attempting to lock the diff. Should I suspect an issue there as well or is this normal behavior given that the position sensor for the 4WD actuator is damaged. I see no easy way of removing it to check.

 

I wouldn't mess with the rod, mark where the gear is before you remove it and install the new one exactly the same as the old one came out so you don't lose your timing.
I'd fix that one first and see if everything works, if it doesn't then troubleshoot it further.

 

1. Rod can be moved by hand or with some gentle encouragement from a plastic hammer or similar. See images here: https://www.tacomaworld.com/threads/transfer-case-stuck-in-neutral.783773/#post-28064912
2. I'd suggest getting all 4 wheels off the ground so the drive shafts (forward shaft and rear shaft) can be turned by hand slowly as you tap the rod if required. Helps with gear engagement/disengagement if required.
3. I'd suggest putting the transmission in neutral
4. Shaft all the way into the transfer case is 2L. Next spot back is 4H. All the way out of the transfer case is 4L. If you need to pull shaft out, an adjustable wrench on one of the flats of the rod comes in handy.
5. If you move the shaft to 2L manually, you'll disengage the front drive shaft. You'll have to manual adjust the timing of the actuator gear and set it to 2L when you reassemble. Lots of post on here on how to do that.


I don't have any first hand experience with the ADD (in the front tcase)....yet....so can't help with that question.