4wd System Operation & Help Thread

See if you can work the gear back and forth and see if it will shift back, you might have to turn it all the way to low and then back.
The way the shift forks in the transfer case operate is kinda funky.

@6 gearT444E what's your thoughts on this? I'm not super familiar with the inner workings of the transfer case but I seem to recall someone else running into this.

 

Truck jacked. Wheel spins and drive shaft is not spinning. So it is in 2H, however light stays on flashing lol

 

So the ADD is unlocked but if you can't turn the front driveshaft the transfer case is still in 4wd.

 

I'll have to continue this tomorrow, it's 1 am here.

 

Thank you for all your help!!

 

Good morning! Great news!

So I spent the rest of my night last night looking online at the best way to get the correct timing. I went back underneath the truck knowing that the truck was still in 4H. So I positioned transfer case shaft in 4H position. And I took main gear out and made sure pins lined up to 4H position according to cover. Which was simple because the 4H position is lined up with the bolt holes for the cover. and 4WD is working properly. 2WD locked in lights went off. Switch to 4H it flashed a few times and locked in. To confirm.
I jacked truck up in 4H and both tires spin and shaft cannot spin freely. I switched it to 2H while still jacked. The drive shaft spun freely and front tires spin independently. Final check was 4LO everything engaged and locked in 4LO

In conclusion, I think ultimate problem was that the grease or whatever it was that was in the actuator cover in the beginning was messing with the contact points and movement around paths. And I also think someone played with it before I became owner and the timing was off.

Questions that I have, should I put some kind of dialectic grease on actuator cover and contact points? Because now it is just straight metal to metal and concerns me that it will corrode faster. Next would it be okay to put some rtc gasket maker to ensure a right seal for cover onto actuator?

@Dm93 i want to thank you for all your help sincerely. I really appreciate the input, time, and help you have provided. Mahalo

 

Yea if I ever get time I plan to pull mine apart and see if I can take some pictures of where it needs to be timed.

It's very possible, I know I had issues with my Clutch Start Cancel Switch not working when it was below about 45F overnight and I took it apart and found the grease they used on the contacts was too thick. Cleaned it up and it's been working fine since.

Thee was some debate about the grease on pages 23-27 of this thread but dielectric grease would probably be ok to put on the contact areas, it definitely needs a bit of some type of grease on it.
If you can't find an o-ring I guess RTV would seal it, just don't overdo it.

 

I don't know what Toyota recommends, but I have some Super Lube, silicone grease that I would use in that situation.
Yes, I'd put some form of light grease in there. Just a nice light film should do.

 

I had my A/C compressed replaced about a month ago. After a week long vacation came home turned over truck and the 4wd and 4lo lights are flashing. Nothing happens when I turn the 4wd selector knob. Not sure where to start. I’ve checked the vent hose underneath and that looks good.

 

This is just a hunch but does your cruise work and do you have an engine light on with EVAP codes?

 

New problem here for me. Decided to take cover off Transfer Actuator to check condition inside. One bolt snapped at head, one snapped halfway up and the last came right out. And the cover will not budge. it seems to be holding fast at the place where the bolt head snapped off. I can get the cover to separate about 1/32" opposite to the snapped bolt but that's it.
Any thoughts?

 

pry and pray, then weld a nut on the broken ones to remove. Worse case you get a cover from a member on here.

 

With the actuator housing being plastic there's not alot of non-destructive options, if you are trying to save it you can try a few light taps with a hammer around the channels where the bolts run to try and loosen up the rust.

Only other thing I'd know to try is if you have a dremmel tool with a cutoff wheel cut a slot down the plastic parallel with the bolt to allow it to expand and hopefully slide off, if your careful you should still be able to re-use the actuator housing just slop a bunch of grease and/or antisize around the new bolts before you put them in.

Once you get the plastic body off mark the gear so you can reinstall it in the orientation and remove it, then you can apply some heat to the aluminum bosses where the bolts go and work on them with some vice grips and they should come out.

 

@Dm93 man you are a saint for getting this info out there, thanks bro!

I lubed the driveshafts on my 2015 when rotating my tires last month and had the 4WD light blink ever since. Front driveshaft is engaged when in 4HI so I figured it was the ADD.

Borrowed a buddy’s multimeter and used this thread to diagnose. Results attached, with incorrect voltage readings highlighted, “x2” just means I checked twice and got the same result.

My plan is to pull the ADD this weekend and see if I can revive it.
If anything else looks amiss please let me know, thanks!

*I didn’t roll the truck in 4HI or LO when testing so I assume that’s why the transfer case 4WD B22 circuit read incorrectly. All other results seem to point to the ADD.

 

Based on your voltages it looks like maybe the shift fork got stuck in the front axle or the actuator is physically stuck, DL1 and DL2 indicate the actuator is in the unlock position but ADD indicates the shift fork is in the locked position.

 

Interesting… probably not an old way to test / troubleshoot that without pulling off the ADD, huh?

I’m about to break out the tool right now.
I have not jacked up the front end with the wheels free to see how they spin. Haven’t noticed any binding on the front axle while driving around town the last week though either

 

I'm just going by where things are according to the voltages you provided, since DL1 and DL2 are the position of the actuator gear and ADD is the position of the actual shift fork it says to me the actuator has turned to the unlock position but the shift fork didn't move to unlock the axle.
You can unplug the ADD Actuator and verify ADD and DL1 go to 12v (you can test this at the actuator connector (Pin 3 (Light Green/Black) is ADD & Pin 6 (Light Green) is DL1) or the 4wd ECU), this will verify those circuits are are not shorted to ground somewhere.
If that test's good then yea you pretty much have to pull the ADD Actuator to see what's going on with it.

 

Pro tip, thank you. There was 12v reading on pin 3 and 6 with ADD unplugged but my dumb ass didn’t think to set back to 2WD before turning the truck off - both 4WD and LO blinking so I guess I’m locked out and spending some time to fix this new problem

just one of those weeks I guess…

 

It should correct itself once the ADD is corrected, if it doesn't we'll figure it out.

 

Ah ok I was about to dive into the forums… guess I’ll get the wrenches out and get to work!

Much appreciated