4wd System Operation & Help Thread

So definitely had a bad ground on pin 18. Fixed that. Cruise control came back. 4x4 lights are still flashing with no function. Cleared the evap codes so we shall see if they come back but I doubt it cause they’re bussed together on that ground.

previous to this had out the new front add in and have another transfer case actuator sitting on the bench.

 

Have you checked the limit switch voltages as outlined in post 1?
Since the actuator has been off it's possible it wasn't timed properly when it was reinstalled.

 

Nah not yet gonna go back out to do that after reading up on it more.mind I’d a good amount of screwing around with this thing back in the day I wouldn’t be surprised if it was even more whacked out

 

still havent gotten to limit switches. but just had key on engine off and 4wd lights flashing and selected 4high and had no action or noise at the transfer case at all

 

I would say your next step would be to either check the limit switch voltages or verify the timing on the transfer case actuator. Since you say the actuator has been messed with multiple times I think I'd probably start with actuator timing verification.

 

The more I think about it the more we talk about it. I’m pretty sure both the front ADD and transfer case actuators are both out of sink, and that is beyond my capabilities at the moment

 

The ADD actuator I believe can only be installed one way, as long as the shift fork lines up with the sliding collar in the front diff it should be good.
The Transfer Case Actuator is kinda tricky to get properly timed, it seems to take most people several tries to get it right. I have yet to mess with one so I don't know of a better way to time it other than trying to line up the contacts like I have shown in the first post with the position the transfer case is in.

 

Search youtube for a vid by the "Care Care Nut" about a caution re: turning off the truck while it's trying to do a 4wd "status" change. I can't find it right now, but if I do, I'll post the link.

 

I found it: forward to: 8:20 - 945. I really dodged a bullet there...(The entire video is well worth sitting for 17 minutes and watching the entire thing.)

https://www.youtube.com/watch?v=Lhx-RMhWyaM

 

Nice find, I'll add this to 2nd post.
That is some good information that I did not know.

 

I love it: "... Only way to fix it is to: "hot wire the freemitz revacilator actuator pins" ??? Jeeze-Louise-Cheezewiz: I love old tech, but this gives me a grey-haired headache! Bottom line: turn the knob only when it's running, has a full tank of gas and you haven't been drinking all day 500 miles from nowhere in the Sierras or suffer the consequences... It's all good.

 

If you haven't seen his videos before, they are all pretty good. I wish he lived in my neck of the woods so I could bring my own truck to him.

 

Transfer case actuator 90% of the people change it the wrong way. The correct way to replace a transfer case actuator is to open up the T case.

 

Yea I've watched some of his stuff but I hadn't seen that one yet.

True but who's going to make a 30 min job take multiple hours to change a shift rod that doesn't wear out. It's perfectly fine to change just the actuator, it just takes a little trial and error to time it properly.

 

Yes: and just to be clear: your contributions here are at least equal to this person with respect to the understanding of the (now) 19-year-old technology of my particular truck. If mine ever starts acting up, it will be your documentation that i will be following to straighten things out. Thank you.

 

It's just how I'm wired, when I run into something that I don't know how it works it makes me wana reverse engineer it to figure out how it works. Since I have one to study I figured why not and I may as well share my findings even though not too many people understand it or are interested.
I looked at wiring diagrams and 3rd gen trucks appear to use pretty much the same system but at least they added scan tool functionality to them so diagnostics on those should be way easier.

I have some more stuff in the works for my other thread too but I haven't had much ambition to work on it these last few days.

 

The guy mentioned in his 4WD video mention as well that the 3rd gen Tacoma 4WD system was pretty much the same as the 2nd, except I think he said they have a new transfer case design in them and the new ECU. Maybe they are the same ones as in the new Sequoia and Tundra.

 

Hi guys. I’m totally stumped. 2010 4 cyl manual trans. Flashing 4wd light on dash and front diff won’t engage. Transfer case seems to work as tc actuator makes noise and front drive shaft spins when in 4wd but cannot for the life of me get the front actuator to do anything.

did the voltage test as described at the beginning of the thread. Here are the results:

 

Looks like a problem with the 4wd detection switch or circuit, unplug the switch (on the rear of the actuator nearest to the transfer case) and check across the pins for 12v, if that's good you may just have a bad switch.
You can also take the switch out and test it, there should be continuity between the terminals with the button depressed.