4WD Blinking Light of Death

I have been having the issue over the last couple of months where when I got to shift my 2018 TRD OR the light for 4WD would only blink and would not ever turn solid. After pouring through forums on Tacoma World I deduced that it was most likely my front differential actuator.

This weekend I replaced the ADD. Upon removing the actuator and the back of the housing I found indeed the motor inside must have been exposed to water because the motor and terminal were corroded. I installed in the new front diff actuator, but when it came to me it arrived in the 4WD position. I installed it and upon turning on the truck the green 4WD light would only blink. I tried resetting the ECU by removing the negative terminals on the battery, but this did not fix it.

I removed the ADD and took off the back on the part turning the gears to move the shift fork over into the 2WD position. I jacked up my truck and moved the differential shift fork to the 2WD position. I verified this because when I spin the front tires the front drive train does not move. I reinstalled the ADD in 2WD position, with the differential in 2WD mode. I reset the ECU, and upon turning on the truck the blinking light of death is still flashing. I tried moving it forward backward, and in neutral and nothing changes.

At this point I drove it to a shop and dropped it off to have it looked at by a professional. They told me that it has nothing to do with ADD, and that all of their codes point to the transfer case motor instead. They also told me to fix it that they would need to split the transfer case apart to install the new motor.

Has anyone had experience with this? It makes no sense to me that it could be the transfer case motor causing this blinking light, when I could drive the truck in 2WD previously with no issues. Also, if I do need to replace the transfer case motor, does it require me to split the motor in half? Please, help. I don't know which direction to go next

 

Have you watched this?

https://www.youtube.com/watch?v=-FZcmDGVEmE&ab_channel=TheCarCareNut

 

Until several days ago when I discovered this video, I too, like Toyota believed taking apart the transfer case was necessary, but no it is not. At least according to this video.

Watch the video here:
How to change Toyota Tacoma Transfer Case Actuator

 

@Toycoma2021 So for people who don't exercise their 4wd regularly and have this issue the op has it would be because the transfer motor doesn't have the strength to move the metal rod for engagement? If this is the case, would doing what is in the video only manually engaging/disengaging the rod numerous times could possibly free the system up again? Just curious. Following you on the spoofer thread and I figured you'd be the guy I should ask this question to. I've torn alot of stuff apart and even managed to get back together but I am not a mechanic.

 

@MosleyKO If you don't believe what the shop said about transfer case motor, why don't you buy a code reader and see what it reads. Or take your Tacoma, to another shop for a second opinion.

 

Me, the one to ask? Don't have the personal experience to offer much more. Only thoughts.

I am learning about these things in case I have problems on the trail and with this new knowledge I think I could remove the xcase actuator and move the rod on the trail if needed, at a minimum. If not put the thing back in perfect alignment - only if I could remember the proper gear clocking.

I also appreciated knowing that removing the actuator box I would not be exposing the xcase to much dirt migration into the case. This was something I was previously very much worried about. No longer.

I did think the reason this YouTuber's gears were out of "time" was that the actuator rod was too stiff to easily move. It seemed the gears ratcheted/slipped out of place possibly damaging the plastic gears in the process. He showed no inclination to inspect the gears for damage or address just what did cause his problem. Just like you, I thought why did he not move the shaft a few more times to possibly loosen it up?

As to Toyota's request that we all exercise our 4x4 parts often? I don't know if it is the actuator or the xcase itself that needs periodic activation. Could be both or just one. My conclusion is that it is better to find a problem with the 4x4 before you need it rather than at the time of need. I really think this is primarily what Toyota is saying.

The more things we tear apart and successfully put back together or unsuccessfully with the project parts being relegated to a plastic bag for later... is how we learn.

In the future I will have the transfer case removed while installing a crawl box and I may try what is in the video. No, I've convinced myself that I will take this apart and make the timing marks more obvious and to see just how much force is required to move the shaft. This could help myself or somebody else on the trail at some point.

 

Caveat: The transfer case codes maybe Toyota specific and not readable by many low and mid-range code readers, or so I have heard.

 

@Toycoma2021 I look forward to seeing the video. Hope you give progress reports on you build as you go. You have my attention.

 

Update: I tore apart the transfer case actuator this morning following the video @Toycoma2021 posted in the thread above. Mine was in a little bit of a different situation being that it is stuck in 2H not 4WD. I pulled apart the motor and looked, and it did not look like it had any damage to the motor or any of the gears. I tried pulling the rod out of the T-Case to shift it into 4WD, but it would not move all the way. I figured I would have to give it some pretty good torque to move it since the guy in the video used a crow bar to put it back into 2WD. I did not want to use pliers on the rod and potentially damage it, so being that it would move I reassembled and timed the motor around it. I reset my ECU and turned my battery on, and the light was still blinking. Accepting that this is most likely an electronical error at this point compared to something mechanical I decided to forfeit and drop it off at the dealership. I will update as soon as I hear back on what they can find out using their code readers.

 

Thanks for the update. This will be interesting. Any troubles when you disassembled the actuator or was it as simple as the video? On a lift, it just might have required having the wheels turning when you were pulling on the rod. But that's just speculation.

 

From what you have written I might have come to a different conclusion. It all depends upon how difficult that rod is to move.

It is a mechanical error that is being detected by the electronics? Thus, showing a flashing light. The inability to easily move the rod is what I am basing my guess upon - that is a physical/mechanical problem.

Understand completely about not wanting to do any unnecessary damage to the rod. Good to stop where you are. I am thinking of a wooden dowel on the tooth part of the rod and a wood piece along the other side all between a pair of vice grips.

Did you take any pictures of the gearing or rod? Mostly interested in the rod as I might want to develop some tool to grab onto it to be able to pull and push it, again, like you without damaging it.

Will be nice to see what the dealer says and if taking the actuator apart sends them in a different direction than they would normally go. Keep all returned parts from the dealer.

 

Very good point.

 

@Toycoma2021 "I might want to develop some tool to grab onto it to be able to pull and push it"
In my line of work I've run into this more than once. With the equipment I have (lathe) I drill a bushing about 3/4 long to the required hole size, split it in half the long way with a die grinder or something similar, then clamp them back together with an old set of vice grips and weld the split bushings to the grips. There is a slew of variation's, alterations you can do depending on the task at hand but I'm sure you get the drift.

 

I can add a bit of security to your statement, as I tore off my TCase Actuator back on Lockhart Basin Rd a couple of years ago.

I was able to work the shaft in and out of the transmission, by hand, in (2) different scenarios: shortly after it happened and I had made it onto pavement (truck transmission in neutral), and then when the truck was back home with the front wheels in the air via a jack and stands.

 

Here is a good overview and troubleshooting of toyota ADD and tcas.

https://youtu.be/efKiKYqwqKg?si=1LmKsHMarx7aZDOn
@21:00, there is a reference to 2006 tacoma troubleshooting
https://youtu.be/jp4pwCs6RuQ?si=u0pIVfqdiC3hUKi2

 

What I have in mind so far is to grab a chunk of metal, likely square or rectangular, drill a hole the size of the shaft and then a hole perpendicular through the side of the large hole for a dowel pin to engage with the linear gear teeth of the shaft. The dowel pin would be sized to fit in the valley of the gear teeth. The shape of the chunk of metal will be so that I can use it to pry the shaft in or out. Prying possibly like the YouTuber did in the linked video in post #3.

Well, on further thought I might have to drill the smaller hole first for alignment and drill deflection purposes. Might require several attempts.

 

I just heard back from the dealer. It after all this BS was a faulty ADD. I thought I ordered this aftermarket part from a reliable source. My next question is if you do need to order this part who would you suggest? The parts from the dealer are almost 600 bucks and I see alot of people going aftermarket on this, the question is which is best to order from?

 

No recommendations on the part source, except keep your eyes open for the dealer sales and for free shipping. This of course does not help in an emergency.

My shop is located next door to an independent mechanic and he has trouble all the time getting new parts that work. Very frustrating for him and his customers.

Good to hear the transfer case timing procedure in the video is correct and you did no harm to the transfer case actuator.

A good scanner or Techstream might have given the correct diagnosis at the beginning. I notice now that you took the truck to a ”professional” in your first post and now you took it to a “dealer”. With differing results.

 

Yeah, I took it to an independent mechanic originally, because I avoid going to the dealer if I can. They are the ones that let me know to go to the dealer, because apparently Toyota has control over the majority of the scanners and equipment to scan and read the codes on their vehicles.

I am hoping the transfer case will still be working properly now lol. I have not been able to test it because I have not been able to get my truck back and locked into 2WD. I ordered in a part from NAPA that I will have this afternoon. So hopefully at that point I can test everything.

 

Your Tacoma still at the dealer, or at independant shop? Get BS, dealers not going install parts supplied from customers, unless OEM. That how it is my location Toyota dealer.