Indexing front axle ADD actuator ...drive rotor?

Good day! I got myself into some trouble this weekend while removing my front axle ADD actuator, and now I need a little help. Please, if you've got a functioning front axle ADD actuator that you are willing to open and snap some good pics, I'd love to see where the drive rotor is indexed inside the housing and where the fork is located. I cannot find a combination of search terms that comes up with any results here on the forum, so I figured I'd start this thread.

Following instructions I found here on TW I removed the actuator by first removing the 4 screws that hold on the black plastic cover, snaking it out, then removed the 4 bolts that hold the aluminum housing to the axle, popped it lose, and snaked it out as well. In the process of wiggling the fork section of the actuator past the subframe, steering rack, trans cooler lines, etc. the "drive rotor" unexpectedly fell out of the housing. I'm usually a stickler for taking pics as I go but that's about the only one I didn't get.

The vehicle in question is the one in my profile: 2001 DCSB AT v6 4x4

I guess the good news is I'm pretty sure I know why its been stuck in 2WD

There is a bunch of corrosion around the o-ring that is supposed to seal the plastic body to the aluminum housing, you can see it in the pics. I believe that's what let the water into the body of the actuator that's caused the issue.


It all seems to have cleaned up just fine, and the motor spins both directions when power is applied to the appropriate pins.


I've sanded down the o-ring sealing surface to get it smooth again, so with some good silicone lube it should be good to go for a while.

Now I just need to figure out how to get it all back together and indexed correctly. Sadly, the truck is down until I get this sorted out.

Any assistance would be fantastic, thanks!!

 

Free bump, hope someone comes along to help.

 

I believe there’s a full thread on add motor timing. Let me do a little googlin’

Here you go

https://www.tacomaworld.com/threads...4wd-add-act-timing-talk-and-positions.580499/

 

Thanks for the bump! Y'all are too kind

Thank you very much for the link and the reply! I did find that thread while searching, but it appears to cover the ADD actuator for the transfer case, and I'm trying to reassemble the ADD actuator on the front axle. Unless I missed something? The layout of the contact traces in the black plastic 'cap' appears to be different in the t-case actuator compared to my axle actuator.

Maybe someone will take pity on me and sell me one of those ADD delete tubes with the stub axle, because I'm about ready to delete the whole system.

 

The second post in this thread almost has exactly what I've been trying to find.

https://www.tacomaworld.com/threads/4x4-actuators-gen-1.456059/

If I end up having to guess at the position of the fork and the rotor, at least that thread gives me some sort of visual reference

 

Holy smokes I think I got it... need to test it on the truck. If so, updates and pics to follow.

 

I don't have experience with the front actuator, but wouldn't a combo of (carefully) rotating the actuator with 12V to one end and moving the ring inside the front diff to one side achieve just that?

 

I actually tried that... the problem is the "rotor" has what looks like 270°+ of teeth around its perimeter but! it doesn't use all of the throw. I can push the fork to the end of its travel, but then I don't know where to drop in and index the "rotor" so that all the contacts line up correctly in relation to the fork.

The motor is generic and it turns infinitely to drive the rotor. As long as it gets power, its going to continue to spin, there is no mechanical switch that shuts it off. The only thing that stops its travel is the computer/controller when it gets a signal from the contacts attached to the rotor that tell it its reached the end of its travel. In theory if the rotor is indexed incorrectly, it has the potential to never send the "stop" signal to shut off power to the motor. From there, the only thing that's going to stop it is logic in the controller (timeout? maybe?), failure of the motor when it burns up, or a fuse pops.

Maybe I should say I didn't know as I think I got it figured out. I'm a little reluctant to pull it all apart again to take pics but I want to make sure to close out this thread with a solution if someone finds it in the future

 

If the actuator operates similar to the rear diff one, it's a simple end-to-end function. So just assemble it, give 12v so it goes to one end, move the fork and mount accordingly. Unless I'm missing something.

 

Nah I don't think you are missing something, its probably that I'm not describing it well. I'll snap some pics tonight

 

OK, so I think I got it:


This appears to be the correct location when the actuator fork is in 2WD

I should stress that I do not know and cannot 100% confirm this is actually correct, so use this info at your own risk.

And as promised, I made a video:




If a picture is worth 1,000 words, then a 6min33sec @ 30FPS video is worth 393,000 words, which is about 3 PhD dissertations. You're welcome.

After reassembly I tested it by crawling under the truck, plugging the actuator into the harness while leaving it hanging in space, and then having my incredibly patient and tolerant wife hit the 4WD button on the t-case shifter. The fork moved in the appropriate direction, stopped when it was supposed to stop, and the 4WD dash light came on indicating it thinks its in 4WD, which means it thinks the rotor and fork are in the correct position. I hope. I'll get everything completely reassembled and fully test it out this weekend

 

And yes, I am aware that the vent nipple is broken off my actuator. I'll be repairing it before its reinstalled

 

That seems to have gone extremely well.


I refilled the front diff with Amsoil

$29 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 GL5 SVG and went for a drive in the dirt. It went in and out of 2HI-4HI-4LO repeatedly without issue.


I ended up using the

$19 Ford XG-8 PTFE Lubricant - 3 oz.

Ford XG-8 PTFE Lube (blue stuff) on the outside of the ring gear and the Dow Corning #4 Dielectric Grease on all the electrical contacts and the outside sealing o-ring. If its good enough for undersea coms cables and outdoor wireless gear antenna cable joints, its good enough for an axle actuator.


The vent nipple went back on without much trouble with some good ol' JB Weld

Here's hoping its good for another ~20years!