Twin Stick Transfer Case Spoofer + Timing Transfer Case Actuator

After a long hiatus I finished my twin stick conversion and got all the factory electronics to work. There’s plenty of documentation on what needs to be done in regards to the mechanical installation of the FJ transfer cases so I’m not going to go over it. When it comes to keeping the electronics happy there are a handful ways of doing it.

1. You can mimic the t-case actuator as shown in this thread; https://www.tacomaworld.com/threads/4wd-ecu-spoofer-for-fj-transfer-case-install.693450/

2. One post suggests that snap on bi-directional scan tools can turn off the 4wd module. (Unconfirmed). The only issue with this that I see is that you would be forced to install an FJ half shaft in the front axle to replace the front axle ADD system.

I have a long standing rule of not tampering with factory wiring harnesses so that was an important consideration for me. I was also looking for the path of least resistance. This method is by no means perfect but it’s within the grasp of most people. It will cost you your transfer case actuator though. So if you’re looking to sell your transfer case this may not be the best option. Or sell your transfer case and buy an aftermarket actuator. I have a 5 spd manual and trying to find a buyer for a 2 year production truck was not something I wanted to do so it was easy for me to tear it up.

The main draw back to be aware of is that when you normally shift into 4WD the system engages the transfer case first. This sends power to the front differential which gets things spinning to the correct speed before the half axle sleeve slides over and engages. With this setup you don’t have the mechanical aspect of it happening. When the sleeve engages the half axle, the speed difference is pretty substantial and you’re going to get a big BANG that’ll shake your truck. I did this going 10 MPH and would not want to do it when going say, 30MPH or faster.

My truck is a manual, I found that while moving I could push the clutch in, switch the t-case from 2WD to 4WD then turn the knob to 4wd and the front ADD would engage smoothly like a factory truck. How all of this needs to be done on an auto truck is beyond me, realistically you probably just need to put it in neutral and coast and shift the t-case into 4wd, but either way be warned! You can potentially blow something up in your front axle if not careful!

How to part:
To spoof the factory system, we’re going to use the factory actuator.

You’ll want to take the cover off the actuator, remove all the gears, release the actuating rod and take the housing off.

Initially I filled the hole the actuator rod comes out of with JB weld, but when it came to coming up with a way to mount the actuator I realized it had to go. Cut this portion off so it’s flush and fill it with your favorite quick setting epoxy. You don’t need to fill it to the point that epoxy gets to the gears, we’re just trying to seal it off from the elements.

This is what it looked like before I cut it off. Frankly I forgot to take a picture after I redid it, so just imagine this portion being cut off, making it nice and flat. More on this later.




Once that’s done it’s time to time the gears.

On the cover make sure the timing mark on the red gear points to the hole.


In the case start with the big gear that has the cam built in it. You’ll want to line up the timing marks as shown in the picture. While keeping the marks lined up put in the intermediate gear between it and the motor gear.

2nd but greasy picture also showing the timing marks.


Put the cover back on and button it all up.

The problem I ran into, and which is why I initially didn’t cut the casing flat is that the actuators between the 3rd gens and previous Toyota transfer cases are different. I was hoping our actuators would bolt right up to the back of the FJ transfer case but it quickly became apparent that it wouldn’t go as I planned.

Get yourself a 3/8” 6”x6” aluminium plate. Make some kind of template and drill holes to match the back of the case. I put a piece of paper on there and used a pencil to try to imprint where the holes were. I missed the mark on one of the holes and it didn’t line up but I think 2x M8 bolts will do. It’s merely holding some weight at this point. There’s no mechanical work being done here.

You’ll want to do some test fitting. I found that with a M8x1.25-30mm bolt I could mount the actuator in the top hole. I then drilled and tapped a 2nd hole into the plate for a second mounting point. If you choose to use the 3rd hole you’ll have to shim it since the mounting leg on the actuator isn’t flush like the other two.



Viola! No lights!


And don’t forget, DO NOT turn the knob into 4wd on the highway without engaging the transfer case first!