4x4 Issues, Front diff actuator or t-case actuator?

Trying to figure out which actuator may be bad. Story is I was driving on snowy roads, rear tires started to slip so I switched it over to 4 wheel drive, heard a large clunk noise underneath me and 4 wheel drive never engaged. I have been reading quite a bit all over the forum about the front diff actuator and the t-case actuator but really don't know which one it could be. The trucks 4x4 light has blinked constantly for the past few days and basically wont go off but remains in 2 wheel drive. I have tried reverse, neutral, and other things to try and get it to engage and it just wont. The truck is a 2006 TRD Sport DC, hoping someone can help me out! Thanks!

 

You could try tapping on each of the actuator motors with a small hammer to see if it'll get them to engage or disengage.

 

Almost same thing happened to me. It ended up destroying my front actuator. Take it off and see if you can manual move the fork. Mine was stuck would not move.

 

Yeah I feel like its the front from what I have read but since the noise came from underneath me it makes me think its something with the t-case. How easy is the front install?

 

man i went through this exact problem last winter and it was an expensive lesson.
i left a parking lot and was slipping coming out so i switched into 4x4 before my tires stopped slipping and it ended up requiring me to buy a new 4x4 actuator (the one attached to the transfer case). the part is expensive as hell and realistically isn't a repair that i was capable of installing so a trip to the transmission shop to install it was required as well.
if i were you i'd consider getting into a warm garage and removing the black casing to see if any of the internal gears are broken as mine were.
this is the part i'm talking about

to make matters worse my front actuator was also not functioning after i got it repaired. once the transfer case actuator was repaired my vehicle was still stuck in 4x4 but if i cycled the ignition with the selector switch in 2wd i could hear the audible "4 clicks" from the passenger side where the computer is. in the end i did the contact solder fix from this link and all has been well since.
http://www.tacomaworld.com/forum/2nd-gen-tacomas/263525-how-trouble-shoot-4x4-actuator.html
hope it all works out

 

You can also manually shift the T-case to force it into 4hi, 4lo, or 2hi. It just takes a 10mm.

 

How do you do that?

 

Remove the three bolts that hold the actuator to the T-case. Pull out on it, you'll feel it click. One click out is 4hi, second click is 4lo. That means all the way in is 2hi.

 

That will get the t-case into 4wd, but still won't engage the front actuator.

 

To lock the front axle in you remove the four 10mm head size bolts, pull the actuator and slide the sleeve toward the driver side to lock, pass to unlock.

Just to really confuse the situation, you can also manually lock the rear diff in the same manner. (if you have the E-locker)

 

Not confusing at all actually. The rear diff is the easy part! Haha.

 

Yah. I hate all of these electrical gizmos sometimes, but it's amazing what kind of trail repairs a guy can do with a 10mm wrench and a screwdriver.

 

Awesome info.

Thank you

 

So I took it in for a diagnostic and they came back saying the 4x4 ecu was bad and needed to be replaced. Has this happened to anyone else? Also said they checked both actuators and they were fine.

 

The chance that ECu is bad is super small.
More likely either case or front is stuck, or one of the position sensors had failed.
Possible that electric engine in the front actuator no longer works because Toyota in their infinite wisdom had not soldered that so connectors split a part.(easy fix with soldering gun)

 

They did say they tested both actuators and it was able to go into 4 wheel drive by bypassing the ecu. Wouldn't that mean both are working properly?

 

Not necessarily. They may work on the lift but not when truck is shaking.
Also motors maybe working but if ECU sees a problem it will not engage them. Flashing 4wd light while you in 2wd is almost always dead giveaway one of the sensors died on you.
ECU is going to cost you a fortune, I would check sensors first as they fail at some point of their life.
4wd does a test when you start the truck and it was not on for some period of time. If sensor is bad ECU will refuse to try to engage.

 

What sensors are you talking about?

 

Position sensors
I am goign to steal somebody's else image.


Look ta transfer case, there are two grey plugs to the right of Black plug connecting to 4wd motor.
Those two plugs are transfer case position sensors, one for 4wd, one for 4Low
There should be one on Front actuator as well.
To remove them you need to unplug them than use wrench to unscrew them.

 

Agreed, there is a very slim chance it's the 4wd ecu. Did they swap it with a good one to prove that's the problem? If not find someone local who would swap with you real quick to see. I'll bet you a box of beer that's not it.