Problem repairing differential actuator (1 Viewer)

[StevenG]

My diff actuator on my 2006 GX470 was very slow to lock, so I decided to investigate.

I pulled off the diff actuator, and it was indeed full of oil. So I ordered a new set of gaskets/o-rings. I saw an excellent YouTube video that showed how to actually disassemble the actuator, clean it out, and re-greasing it:

https://www.youtube.com/watch?v=92WwOsLc39E&t=22s

I tried to be careful not to move the gears in the process, put it back together, re-installed the actuator on the truck, and it doesn't work (center diff doesn't lock, and a bunch of dash lights are on (check engine light, VSC, etc; you know, the same lights that come on if your gas cap is bad).

So I removed the actuator again, took it apart again, rewatched the video to make sure the gear timing was right, put it back together and re-installed it, and same result.
What I noticed is that the first time I installed the actuator, I could hear the motor trying to do it's job before all the dash lights came on. The second time I installed it, I didn't hear the actuator motor even trying to do anything.

Does anyone have any suggestions?

Is there a way that I can reset the electronics so that it tries moving the motor again? Would clearing faults with an OBDII device get it to retry the actuator motor?

If I should just give up and buy a new actuator, where do you suggest I buy it from?

 

[StevenG]

My diff actuator on my 2006 GX470 was very slow to lock, so I decided to investigate.

I pulled off the diff actuator, and it was indeed full of oil. So I ordered a new set of gaskets/o-rings. I saw an excellent YouTube video that showed how to actually disassemble the actuator, clean it out, and re-greasing it:

https://www.youtube.com/watch?v=92WwOsLc39E&t=22s

I tried to be careful not to move the gears in the process, put it back together, re-installed the actuator on the truck, and it doesn't work (center diff doesn't lock, and a bunch of dash lights are on (check engine light, VSC, etc; you know, the same lights that come on if your gas cap is bad).

So I removed the actuator again, took it apart again, rewatched the video to make sure the gear timing was right, put it back together and re-installed it, and same result.
What I noticed is that the first time I installed the actuator, I could hear the motor trying to do it's job before all the dash lights came on. The second time I installed it, I didn't hear the actuator motor even trying to do anything.

Does anyone have any suggestions?

Is there a way that I can reset the electronics so that it tries moving the motor again? Would clearing faults with an OBDII device get it to retry the actuator motor?

If I should just give up and buy a new actuator, where do you suggest I buy it from?

Disregard what I said about the dashboard lights; that was an unrelated problem that I cleared with an OBDII reader. The diff actuator not locking is still the problem. I guess I'll order a replacement unit.

 

[xcmountain]

Steven, do you have power to the actuator? I would assume yes because you heard the noise before. Is there a fuse associated with said actuator? Check that. Do you have a power probe that you can bench test the actuator? Also how many miles on your GX?

 

[StevenG]

Steven, do you have power to the actuator? I would assume yes because you heard the noise before. Is there a fuse associated with said actuator? Check that. Do you have a power probe that you can bench test the actuator? Also how many miles on your GX?

Good questions. GX has 128k miles. I believe the actuator is receiving power because I hear beeping noises in sync with the flashing diff lock light on the dash, but I guess I'm not sure where the source of that beeping is coming from. I don't know what fuse provides power to the actuator; if anyone else has a wiring diagram and can identify which fuse I should check, I'm happy to do that.

 

[xcmountain]

Good questions. GX has 128k miles. I believe the actuator is receiving power because I hear beeping noises in sync with the flashing diff lock light on the dash, but I guess I'm not sure where the source of that beeping is coming from. I don't know what fuse provides power to the actuator; if anyone else has a wiring diagram and can identify which fuse I should check, I'm happy to do that.

So she's pretty young mileage wise and we can mostly rule out failure because of age. If I remember correctly the beeping is normal per Timmy the Tool man's video.
When is the last time it operated properly?
Have you tried engaging it with just the actuator hanging there instead of being installed? I don't know if you can manually engage that rod or not but just a thought., in the event there is a physical limitation the motor cannot overcome.

 

[StevenG]

So she's pretty young mileage wise and we can mostly rule out failure because of age. If I remember correctly the beeping is normal per Timmy the Tool man's video.
When is the last time it operated properly?
Have you tried engaging it with just the actuator hanging there instead of being installed? I don't know if you can manually engage that rod or not but just a thought., in the event there is a physical limitation the motor cannot overcome.

Well, I guess that depends on what you mean by "properly". My motivation for taking this project on is that the diff lock has never locked rapidly for the entire two years that I've owned it. It would lock eventually, but only after approximately 15 flashes of the light on the dashboard. Last summer I had trouble getting it to then unlock once, so I decided to work on it because it's always acted a bit fussy, but it would generally lock and unlock eventually.

When I removed the actuator the first time, it was obviously filled with oil, so we know that the gasket around the rod was bad. But after replacing the gasket and re-installing it on the truck, it has never worked again. So now it's completely non-functioning, and I'm thinking I should just buy a replacement actuator assembly on eBay or something and start over again.

 

[xcmountain]

I understand. Did you regrease the gears when you took it apart? Unrelated some of the lubricants Toyota uses get stickier and stickier with age, for example, the sunroof on my 3G 4R, the tilting steering column on this vehicle will almost seize because of it,,, and last but not least my wife's window bits in her 1G Sequoia. I recall or at least I think I do, Timmy cleaning the grease out and reapplying prior to installation. The delay in engagement makes me think of friction, which makes me think of sticky grease. Admitted failing electronics can do this as well but like the previous suggestion just a thought in the troubleshooting arcade.

 

[StevenG]

I understand. Did you regrease the gears when you took it apart? Unrelated some of the lubricants Toyota uses get stickier and stickier with age, for example, the sunroof on my 3G 4R, the tilting steering column on this vehicle will almost seize because of it,,, and last but not least my wife's window bits in her 1G Sequoia. I recall or at least I think I do, Timmy cleaning the grease out and reapplying prior to installation. The delay in engagement makes me think of friction, which makes me think of sticky grease. Admitted failing electronics can do this as well but like the previous suggestion just a thought in the troubleshooting arcade.

Yes, I did re-grease the gears, and before installing the actuator I confirmed by hand that the rod moves in and out of the transfer case smoothly.

 

[xcmountain]

Well, Steven, I am with your original direction. New actuator. I hate when parts cannot be resurrected.

 

[StevenG]

Does anyone know the distance the rod moves when switching the center diff between locked and unlocked? I'm surprised by how small the movement appears on my GX; I'm guessing it's less than 1 inch (maybe 1/2" or 3/4"). The rod moves smoothly between the in and out positions, but it's not very far. Normal?

 

[xcmountain]

Check this out.

Toyota-4Runner.org

The Largest 4Runner Community in the World

www.toyota-4runner.org

 

[fvedmo]

Check this out.

Toyota-4Runner.org

The Largest 4Runner Community in the World

www.toyota-4runner.org

Man that's a huge big ole thread. I'll have to get into it, my CDL is taking a really long time to engage. Disengages fast, but doesn't want to seem to engage. Have to drive quite a bit and turn quite a bit to get the CDL light to stay on. Tested fine after I did the twist and pull of the actuator to replace the seals but now I'm wondering if it is out of time.

 

[StevenG]

If you can get the diff to lock/unlock (that is to say, the dashboard light will light/go dark solidly without remaining blinking continuously), then I think your timing is fine. I had to replace the entire unit on my GX470.

 

[fvedmo]

It does get there, but the engaging takes a looooong time like driving 100s feet and lots of turning. Maybe i should try the engage in neutral method, but I thought i had read previously that it finds its way better in motion.

 

[StevenG]

It does get there, but the engaging takes a looooong time like driving 100s feet and lots of turning. Maybe i should try the engage in neutral method, but I thought i had read previously that it finds its way better in motion.

I engage mine with both the transmission and the 4hi/4low lever in neutral. That seems to be the most reliable method on my GX.