4wd System Operation & Help Thread

I have no answer for you there, according to the voltages it was in 2H when you checked it.

 

Just lurking here and remaining quiet for the last several days through the process and progress, and being a good student that just listens and learns. I wanted to just say that nothing drives home the: "Use it or Lose it" advice that we have seen and heard so often on this forum than the picture of the actuator interior in post 423. What a great thread, and what a classroom this has been. Thanks to all.

 

Yea it looks clean in there, not sure what could have been keeping TL1 grounded. There wasn't any moisture/corrosion in the connector was there?

 

You have nothing to lose by cleaning it and reassembling it.
I can see that the ground trace looks darker up to the point where it reaches 4H.
But I think that has more to do with it being put in and out of 4H more.
You can actually see grease build up in that spot.

Take a good look at the connector as @Dm93 said.
Make sure you don’t see any corrosion.

 

Negative, no moisture or corrosion in the connector.

Cleaning now, got to put the kids to bed too, but should have a test within the hour.

 

Is my assumption correct that in the end: the fix that brought the system back to life was a standard: test-inspect disassemble-clean-relube? You have my word that I have read through this thread twice to confirm this and I didn't see a "hard fix" in the reading. (I can't really bring myself to use or add the word "simple" or "easy" to the solution wording because IMO it was neither) I would be OK with adding thorough and methodical somewhere in there there.

Outstanding work guys.

 

Using the 4WD system on a regular basis is a preventive maintenance procedure on these trucks.
It will help the system keep contact “better”.

This is of course only if the actuator is sealed.
Once water enters the system, it’s a matter of time.

Check the vent hose yearly.
And use the system every 2-3 months (or more).

 

Well for that one it was but every case is different, that's why it's always better to know exactly where the problem is by testing even though it may take a bit of time to correctly identify the problem. Better than replacing both actuators and an EVAP canister only to find out there's a broken ground wire as we have seen before.

 

Thank you. Thanks to this forum I learned of this advice when I was looking through here after my son got his 2005 about 5 years ago. I got my 2014 two summers ago in 2021 and have engaged and exercised the system in my driveway at least once per week, and out on a nearly straight six mile section of road near my home at least once per month, and especially every time we get rain or snow. Summers take care of the chore when I'm up in Maine and New Hampshire fishing. The vent hoses are in place and appear to be in good shape.

 

I’d be lying if I said I engaged mine weekly.
I try to at least once monthly, but I’ve forgotten that a few times too.
What you don’t want to do is only use it in the winter like most people.
That is a bad time to find out it doesn’t work. Or worse, only use it once you are stuck.


For me, once monthly seem enough.
But more often certainly won’t hurt it.

 

Well gents, it works, 4WD engaged immediately, disengages, and functions normally!

Cleaned it up, loaded dielectric grease, and put it back together. Amazing, I’m so appreciative for your info and guidance, and super stoked I didn’t blindly throw parts at it!

 

The boys are 2/2 tonight holy shit

 

Yea I never thought this would become as successful as it has when I put it together, it was initially me just wanting to know how the system worked and the logic behind it then with the amount of people posting about 4wd problems I decided to gather as much info as I could about it and post it here.
With the research I've done for my other thread at some point I'll have reverse engineered the whole truck at least electrically.
Currently doing connector pinouts of all the junction connectors for 05-08, that's becoming quite a task but it's moving along.

 

If people only knew the amount of work you have/are doing behind the scenes.
I’ve seen the pictures and the .xls files. If you get done, what you are working on.
There won’t be a more comprehensive guide to the 2nd Gen Tacomas. Even Toyota would be envious

 

I think one of the most valuable pieces of this thread (for me anyway) were the sequence of pictures showing the disassembled control actuator motor, initial interior shots after the cover was removed, pics of the gear wheel, the inner contacts, re-lube and prep and more. Seeing it apart this time finally made it "click" for me and understand clearly what goes on in there when you turn the knob as well as confirming a possible repair was possible, (and reasonably likely) without removing it and/or replacing it. The simplicity of it also impressed me.

Those pictures and the narrative back and forth between the main players convinced me that if mine ever starts acting up, I can do this too: at least this initial testing, disassembly and inspection without tiny springs and little ball-bearings flying everywhere to disappear forever (ask me how I know) and ending up with my truck on the back of a flatbed going for a ride to the dealer.

 

Yes, that picture of the actuator disassembled is much easier to read than the diagram in FSM.
Once you understand how it works, the diagram make total sense.

I take it you too were confused at first.
Until I had a good understanding of how the system worked, theses 2 pictures had nothing in common.

 

I was confused and unclear from the past pics of the circular contacts (inside) all alone in the pictures of the cover. I still don't have a severe-clear visibilty picture in my head, but I'm getting there. Let me know if I have it correct now: I have it in my mind as a cover: remove the bolts, remove the cover and turn it over and there are contact paths underneath. (Like a distributor cap) The light finally went on when I saw the pic of geared contact wheel with the three contact fingers in focus all alone in there: It's the last piece at the "bottom" sitting next to the transfer-case housing. Leave it alone and clean them in-place. Somewhere underneath it, on the edge of the circular housing is another hidden gear turned by a electric motor. Those pictures also drove home what the penalty would be if you were to remove it without thinking or not knowing what you were doing. Conversely, it also made clear why you really didn't have to remove it. It looks like you could do delicate surgery to clean and lubricate those three parts right in place. The contact "runners" look robust, but I would treat those three sprung contact fingers with a wary surgeons delicate touch if trying to clean them or more risky: attempting to adjust them. I didn't understand the labels TM1, TM2 and TM3 until today. They are the pathways to the hidden spring fingers. (I hope)

 

The electric motor is on the piece you take off.
The motor turns a worm gear, that turns the big gear you leave on the truck.
Under the big gear, is smaller reduction gear. That gear drives (pushes) the shift rod.

Motor



Worm Gear



Big gear (driven by worm gear)


Reduction gear and shift rod (picture is from a 1st Gen, operation is the same)

 

OK: Got it! The pic (#3) with the toothed wagon wheel look is the first thing you see when the cover comes off: and there are the three little contact fingers that run along the circular paths on the cover barely peeking out from the globs of yellow grease. Leave it in place. Thank you for sticking with me through this. It makes perfect sense why regular operation of this system helps to keep the contacts communicating and why long-term hibernation with no exercise, heat, cold, old grease and condensation causes contact problems.

 

Correct. Leave the big gear with 3 fingers in place.
Do NOT remove it. Clean it while it’s still in place. (On the truck)

If you have to remove it, MAKE SURE to mark the position it is in.
Put it back in exactly the way it came out.
Do NOT press the shift rod in or out. Other wise, you will have to retime the actuator.
You do not want to do this.
Again, don’t remove it unless you HAVE TO.