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Discussion Starter · #1 ·
Hey guys,

I've tried searching high and low but I get a lot of mixed response about what I can do to get 4lo working again on my 05 Sequoia. It's important to note that is an 05 which has the 5 speed automatic and fully electronic transfer case (no shift lever for the transfer case).

I bought the vehicle this year and I identified during the sale that 4lo did not work, frankly I wasn't overly surprised - who knows if it had ever been used by previous owners and lack of use doesn't do these things wonders.

I realize that to replace the actuator assembly completely in this transfer case the transfer case itself needs to be split open to remove a retainer on one of the shafts of the actuator - what I want to do is completely exhaust all viable options before doing that. I would probably try to source a used transfer case and simply swap it out before doing that considering the actuator is >$1000 just for the part and with the labor involved at the dealership it would probably run close to $3000 all said and done.

I believe I am following the correct protocol for shifting into 4lo - I get it into 4hi (with or without the center differential lock on, I've tried both ways - that does work fine) but I do not hear a motor trying to move in the actuator. I've tried parking the vehicle on a grade and released the brake slightly enough to allow the vehicle to roll while in Neutral to try and help mesh the chain in the transfer case - but still nothing.

There is an electrical connector and vacuum hose run to this actuator - I've checked the electrical plug for corrosion and there is none. I've also checked the vacuum hose and i I can't find a split or break anywhere. I've tried tapping on it with a rubber mallet and a hammer while it was trying to engage 4lo and still nothing.

One thing I find really strange - with the actuator trying to engage 4lo - when I get underneath the truck I can definitely hear a beeping noise coming from the actuator??? It actually sounds like there is a proper beeper inside it, seems like 1 second beeps followed by 1 second pauses. I am fairly certain there is no beeper in the actuator so does anyone have any idea what that could be?

I read one thread where a member removed the three bolts holding the actuator motor on and simply "wiggled it" around and that actually got theirs to work - this did not get mine to work though.

Is it possible to take apart the motor to reveal any contacts that could be cleaned? I found a thread where a member did that, but was this on the earlier transfer case mated to the 4 speed auto?
http://www.tundrasolutions.com/foru...94-how-change-transfer-case-actuator-without/

There are lots of screws holding the motor assembly together but I do not want to go to far with the disassembly of the motor and ruin it such as in this thread:
http://www.tundrasolutions.com/forums/1gen-sequoia/225435-2005-sequoia-4wd-transfer-case-acuator/

Any help would be very much appreciated. I'd love to have functional 4lo again in my truck.
 

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Discussion Starter · #3 ·
Well after expanding my search to include the 4Runner guys I may have found something:

Transfer Case Actuator - Toyota 4Runner Forum - Largest 4Runner Forum

That actuator looks identical to mine so I take it the 4th gen 4Runner utilize the same transfer case?

Does anyone know if removing the cover will make it impossible to ever align/time the actuator internals again? i.e. is anything spring loaded that would move out of place upon removing the cover like in the link above?

I have a feeling that I still won't be able to access the 4lo motor/gear assembly upon doing what the above post mentions, it is my understanding that there are two motors in the actuator and the one for 4lo is buried underneath the other..

C'mon guys any help on this would be great - there's not a lot of info out there. I'm really surprised more people aren't plagued with this problem. It actually seems that gear oil leaking out of the transfer case at the actuator is the more common issue discussed by the 4Runner guys.
 

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Discussion Starter · #4 ·
Below is probably the best resource I found to date - I think it's the same actuator even though this is for a 2004 4Runner

2004 v8 4x4 actuator replacement - Page 2 - Toyota 4Runner Forum - Largest 4Runner Forum


Unfortunately this thread doesn't go into much detail about the timing of the assembly - or more specifically if it is possible to keep it in time. What a pain in the.....

I guess I'll just keep trying what I've already done - get under the truck and tap strategically on the actuator with the misses inside repeatedly cycling the 4lo switch. Persistence paid off for this guy: http://www.toyota-4runner.org/4th-gen-t4rs/62382-new-guy-fixed-4lo-my-runner.html
 

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Discussion Starter · #5 ·
Well, if nothing else this thread is at least becoming a consolidated location for different resources on this problem.

I managed to find a thread where someone rebuilt their transfer case actuator (it was in pretty rough condition). A lot of good information in this thread...

4lo Actuator Rebuild - Toyota 4Runner Forum - Largest 4Runner Forum

Unfortunately it doesn't seem to have "happy rainbow" ending, it seems to have worked but from what I can tell was not timed correctly. You'd think with enough photos and marks before disassembly that it would be possible though?
 

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That's a breather hose, if you look on the driver's side of the engine compartment you'll see two silver caps with black hoses running to them. One is the front differential breather, the other is the transfer case. The 4WD system is entirely electronic.

Do you have a transfer case (2HI/4HI/4LO), or a locking center differential (2HI/4HI+open/4LO+locked)?
 

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Discussion Starter · #7 ·
I have the locking center differential (2HI/4HI+open/4HI+locked/4LO+locked).

I am aware it is fully electronic - It's the electronic actuator to shift the transfer case I'm having issues with. It has two motors, the one for 4HI and locking the diff (it's the same motor) is working fine. When I try to engage 4LO the other motor makes beeping noises but cannot shift the case into low range.

I haven't had a chance to try the "tap on it every conceivable way + actuate it repeatedly" method yet as I've worked 6 straight 12's this week. Hopefully I'll report back in the next few days with some news....
 

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Discussion Starter · #9 ·
Ahh okay thanks for the clarification on the breather hose. Everyone does refer to it as a vacuum hose and I couldn't for the life of me figure out why an entirely electrically drive actuator would need vacuum...

I think I know what I need to do at this point - it's just a matter of seeing if I can get my actuator to work again without having to perform surgery or not. I don't expect to get any additional information now, I think I have it all in this thread...
 

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So... I know its an old thread, but i figure someone in need will find it.

I have had the nightmare of a week with my 2006 Sequoia t-case (center diff/4lo-4hi) actuator. #1 problem being that I failed to record where any of the timing was when I took the center diff gears off the second time. I took the center diff portion completely out to the bench and using the service manual continuity tables to deduce where most of the key spots are on the timing gear, confirmed by then putting it in and trying the different positions on the motor and dash light response.

The final piece is realizing there are two motors and two shafts... one for 4lo / 4hi (tucked up inside) and one for center diff (visible when you first pop off the cover). My Sequoia is stuck in 4lo so I have to get in there and free it/check the motor. Most likely my breather tube letting in water is the culprit since it was flopping around on the transfer case when this all started after a hard puddle day, and I'm optimistic since everything in the actuator has been clean as a whistle, but clearly recently had a little run in with off road water fun.

I am going to do a better job marking timing this time when i take out the 4lo section so I might not be any help with that if you messed that timing up. BUT I will get on an post my all my center diff/lower motor timing and I will put in anything I learn about the 4lo /4hi timing. I'd love to put it manually into 4 hi, but that might be tempting disaster again with the timing gears.
 

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All right here's the skinny.

Pop off the cover and you're looking at the center diff shaft, gears and motor. There are actually three positions for the center diff: all the way out is where it sits for 4WD and Unlocked; in the middle is Locked; and all the way in is 2WD Unlocked. Yes, I know the center diff doesn't have anything to do with 4WD, but that's the way toyota made the actuator/transfer case. This is probably why when you engage the 4WD from 2WD, the center diff light blinks because the actuator is passing the center diff through the Locked position.

As for the timing, you can pretty well discover your timing, because there are only so many combinations possible. The best way I know how is to put the actuator into 4WD (4hi or 4lo). Repeatedly try different places for the timing gear while turning the car to the "ON" position (a friend helps this go really fast) until the center diff motor doesn't run when you turn it on... This is the the center diff all the way out 4WD Unlocked position I was talking about above.

As for the the 4hi 4lo motor gears and shaft, (these are the ones hidden in the top of the Actuator) Yep, You have to remove the actuator from the transfer case to get to it because the center diff shaft prevents the inner/inbetween cover from coming off. BUT you can stick 12 v DC leads on to the 2 lowest pins closest to the transfer case to manually operate the 4lo 4hi motor. That was the ticket for me. Apparently not enough voltage or amperage was reaching the motor because as soon as my "stuck-in-4lo" motor received the full jolt it instantly came free. I reversed the leads and did this a few times... putting it back into 4lo and having a friend engage and disengage 4lo 4hi. A buddy is also helpful because even if you put the car in neutral to do this the transfer case may still be bound up and a little roll forward or backward will help the actuators go in and out smoothly.

The next day we were actually out on the forest highway and turned off the car for a sec. The original short that I have in the actuator tripped again and sent it to 4lo. #$%^@#! But having all my recently acquired knowledge on the actuator, I quickly jumped underneath and sent to hot 12v leads and freed the motor again to the 4hi 4lo shaft. Back on the road. Did a 300 mile trip this weekend no problem.

Only trick now is to see what kind of grease i can shoot in there and what I should use to help the electrical contacts that show a little sign of rust from tripping when the car just happens to be in neutral and sends it into 4lo.
 

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Totally forgot: the eccentric gear that moves the center diff shaft. For the 4WD Unlocked position I talked about, the short side that won't trip the other timing sensor switch should be in that position. IT actually took a couple of tries to see if it should be close to engaging the second sensor, or the middle, or the back. but definitely want it in the position that the sensor switch is open (not tripped).
 

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All right here's the skinny.

Pop off the cover and you're looking at the center diff shaft, gears and motor. There are actually three positions for the center diff: all the way out is where it sits for 4WD and Unlocked; in the middle is Locked; and all the way in is 2WD Unlocked. Yes, I know the center diff doesn't have anything to do with 4WD, but that's the way toyota made the actuator/transfer case. This is probably why when you engage the 4WD from 2WD, the center diff light blinks because the actuator is passing the center diff through the Locked position.

As for the timing, you can pretty well discover your timing, because there are only so many combinations possible. The best way I know how is to put the actuator into 4WD (4hi or 4lo). Repeatedly try different places for the timing gear while turning the car to the "ON" position (a friend helps this go really fast) until the center diff motor doesn't run when you turn it on... This is the the center diff all the way out 4WD Unlocked position I was talking about above.

As for the the 4hi 4lo motor gears and shaft, (these are the ones hidden in the top of the Actuator) Yep, You have to remove the actuator from the transfer case to get to it because the center diff shaft prevents the inner/inbetween cover from coming off. BUT you can stick 12 v DC leads on to the 2 lowest pins closest to the transfer case to manually operate the 4lo 4hi motor. That was the ticket for me. Apparently not enough voltage or amperage was reaching the motor because as soon as my "stuck-in-4lo" motor received the full jolt it instantly came free. I reversed the leads and did this a few times... putting it back into 4lo and having a friend engage and disengage 4lo 4hi. A buddy is also helpful because even if you put the car in neutral to do this the transfer case may still be bound up and a little roll forward or backward will help the actuators go in and out smoothly.

The next day we were actually out on the forest highway and turned off the car for a sec. The original short that I have in the actuator tripped again and sent it to 4lo. #$%^@#! But having all my recently acquired knowledge on the actuator, I quickly jumped underneath and sent to hot 12v leads and freed the motor again to the 4hi 4lo shaft. Back on the road. Did a 300 mile trip this weekend no problem.

Only trick now is to see what kind of grease i can shoot in there and what I should use to help the electrical contacts that show a little sign of rust from tripping when the car just happens to be in neutral and sends it into 4lo.
so I’m having the same issue with my Sequoia. I have a couple of questions if that’s OK:
-Can I actuate the 4low motor just by using the two pins that you are discussing while it ISD on the tcase?
  • Does the vehicle have to be running or at least in the on position to do so?
  • Does it matter which position the button was in when I disconnect the wire harness from the actuator?
-Any other tips? I may try that this weekend. Thanks for your informative post!
 

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My wife bought the 2006 Sequoia with 100K on it and 4LO hasn't worked in 87K miles....I just don't worry about it because it is strictly a pavement pounder. I have a 06 Tundra if I ever need 4LO.
 
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