2007-2020 Transfer Case Actuator

Checking the ADD (front diff actuator). Diagrams are from a service manual for MY15-20 but the ADD is the same down to MY11 as far as I can tell. Use at your own risk. Recommended if you have any doubt your ADD is timed/functioning correctly that you do this with the ADD removed. If you leave it on the truck and make the connections and a limit switch is malfunctioning you could ruin the front diff altogether.

 

Here are my findings on the selector switch. This seems to be the correct operational voltages unless someone wants to correct me (if you do, I will have found a smoking gun as to why my actuator is unresponsive.) The illustration is viewing the back of the switch.

 

Hey folks. Hoping to get a little clear on how the 4HI and 4LO works. My truck switches into 4HI with no issue, and for a while it switched into 4LO, but had a tough time getting out. Now it won’t switch at all into 4Lo. So after reading everything here, I figure the transer case actuator puts her into 4wd and the front diff actuator selects lo or hi? I’m obviously confused, and I don’t wanna just throw parts at the problem. Can someone please break it down for me?

 

Your trying to go into 4LO in Neutral right. So in 4HI you'll stop, hit neutral, hit the 4LO switch and hit Drive right?

To get off you do the same in reverse.

 

Correct. 2wd to 4hi while moving slowly, sitting still in neutral to 4lo. Sometimes letting it roll a tad to see if it engages. Sometimes I hear tge clunk, but 4hi and 4lo both blink, but remains in 4hi.

 

BlueRibbon, the front diff actuator is just an electronic version of locking hubs. Older 4wd systems (pre-2000s) you would have to get out of your truck, turn the little knobs on your front hubs before you engaged the transfer case to get into 4wd. The front diff actuator just replaces all of that with a fork on a sleeve that will connect the two front half shafts to the front differential gear.

2wd to 4hi:. Transfer case hi actuator engages to link front drive shaft then the front diff actuator engages to couple the front half shafts.

4hi to 4lo:. Transfer case lo actuator engages to give the lower ratio for hi torque situations (let me tell you, 4lo can move some stuff in these trucks if you have the traction).

I believe the transfer case actuator for touch select 4wd (MY 15) is different from the 2009-2014 based on a service manual I stumbled across. I could be completely wrong but the section refers to a wf1am which is a single gear motor vs my 2011 which is a two gear motor type.

I'll have to find that redirect link again to that manual. It has a lot of troubleshooting you can do if you are handy with a DMM and a screwdriver.

 

Holy crap thank you so much for your explanation. I’ll search foe the manual as well. As far as I could tell behind the transfer case, I also have the single gear motor, not the dual gear motor which is all I could find any information as well as an aftermarket part. The OEM single gear motor runs over $1K, and a used one is around $800 on ebay. But if I can find some troubleshooting tips that would be awesome.

 

This would be for the pre-2015 Borg Warner transfer cases right? I have a 2015 and I can't find anything that looks like whats in the videos or pictures.

 

Hey so I found this write up on the transfer shift actuator assembly on the borg warner transfer cases (2015+).

https://www.ttundra.com/1493/transfer_shift_actuator_assembly.html

 

Quick question, I see this part in the original post:

"Brought the truck home and inspected. Noticed vent hose not connected. Removed top cover to 4-Hi motor. Motor was rusted and frozen."

So I'm super interested in learning 2 things: where that vent hose is at, and its outer diameter so I can get a nice stainless steel clamp 'round it.

 

did you keep reading or stop there? because there are myriad comments describing that hose, complete with photos pinpointing its location

 

No, all I found was some Word docs with grainy YouTube video screenshots. If no better photos exist, I'll take some better ones when I check mine.

 

So I found my culprit after rechecking everything including DMM all harness terminals. A squirrel chewed through the front ADD harness (segment that comes off the control unit through the firewall.). This is behind the passenger headlight right on the frame rail. You can access it easily from the wheel well by removing the front rubber inner fender liner. I am in process of doing a proper repair but when I did a temporary everything worked as it should when I flipped the switch. Teaches me for leaving her outside and not driving it but once every 5-8 weeks. Time to clean out the garage and get her tucked back inside.

 

Another handy diagram I found for checking the transfer case 4hi actuator. If you make these connections and it turns and stops with the gear opening near the mold marks in the casing (electrical wipers right at about noon when viewing the motor as bottom and perpendicular to noon), your actuator is very likely in good condition. Still trying to figure out the 4wd to 2wd diagram. My gut tells me to reverse 1&2 on and put lead to pin 4 on pin 5 but I haven't tested yet.

 

@JibbaJibba56, I've tried everything on these threads to troubleshoot my 4HI issue and believe its down to an electrical issue. (linkage engages/disengages, actuator motor runs fine, microswitch seems ok, etc). When I first noticed the problem, I found the wire coming out of the 4HI ADD (pin 7 GND in your diagram) was broken. Not being able to find a new 7-pin connector, I coerced the receptacle out of the connector and soldered in an extension of wire. WHen I first plugged it in I saw the motor turn when I turned the 4HI selector. I reinstalled the housing assembly, connected wires and tried again. The motor ran and sounded like it engaged the drive pin, but 4HI still blinking. Since then, I haven't been able to get the motor to run again with the 4HI selector. (I can still move the motor using a 12V power supply).

I'm thinking my dirty fix of the connector is to blame, and I probably do not have good contact from the ground. Question for you, where can I test continuity of these wires? Do you have a diagram from the 7pin side on the motor to the 6pin connector you show that was damaged?

Also, does anyone know where to get a new 7pin connector, or any port of that wiring harness? I am coming up with no good options online.

Thanks

 

Post 121 shows the front ADD connector on motor housing as 6 pins. The 4hi transfer case actuator is 8 pin (post 134). Post 134 is unrelated to the damaged wiring connector I found I just thought I'd share a proven and safe method to test the transfer case 4hi actuator with a relay and allowing the gear to move to a timed position for the next person that is experiencing issues. I have literally tried everything to troubleshoot mine and made some diagrams of what I did.

 

Hello, also having 4hi flashing light and lack of engagement issues. I took the 4hi top part of the actuator off and mine looked pristine, cut the shitty section of the vent hose off and slid it on with good connection. In this youtube video, the actuator motor moves and clocks into the correct position when the top is removed from the housing but stays plugged in.
https://www.youtube.com/watch?v=SWn6FupdrdI

I tried this with mine and get nothing, i check the motor and it works strong when connected to a 12v, spins the gears no problem. when its plugged into the harness but not attached to the actuator housing, i turn the truck to the on position(no started) and nothing happens with to the gears, no clicking no movement etc.

 

Start looking for rodent damage to wiring. See post 133. If you want to verify off the truck that your actuator will move to timed position see guidance in post 134.

 

Thank you for all the info. Where can I find the relay for the ADD? Is that something that can be replaced. I'm having the 4 hi flashing but only when below freezing. The TC actuator is in good shape and doing what it's supposed to do. If I park the truck in 4wd it's fine in the cold. if I do anything with the switch in below freezing weather I get the flashing and beeping from front end. Absolutely no issues if it's over 32 degrees. TIA

 

Anyone have issues with the 4hi rod not going all the way in beside V@por? I can get the rod to come all the way out showing the 18 teeth and sime excess, but when i push it in, it'll only go in a little bit with about 14-15 teeth showing. Still won't go into 4hi.

Edit: I could be wrong but i think the 5.7L and 4.7L motor have different transfer case. Maybe the 4hi rod in thr TC on the 5.7L go all the way in, but on my 4.7L, it goes in enough to show 14-15 teeth. I set the timing as the OP and i can hear the motor turn. New issue is that the front drive shaft is locked in, but front wheels aren't engaging, so heading to look at the Front Differential Actuator new. I think that's my next issue.

 

<a href="https://www.tundras.com/threads/4wd-wont-engage.124426/#post-3187424">4wd Won't Engage</a>

 

Howdy friends. Well, I joined the illustrious family of tundra owners about a year and a half ago, and then I joined the elite club of tundra owners with non-functioning 4 wheel drives.

The 4x4 went out just in time for the heaviest winter I’ve seen in all my life living in the central Sierra Nevada. Luckily I still have my old ‘88 yota 4x4 pickup that has never let me down yet.

Anyway, long story short, after getting by without 4x4 in the tundra all winter, I finally got around to messing with it a couple weeks ago. I opened up the 4-hi t-case actuator, and sure enough the vent hose was all split and loose, the 4-hi actuator was full of water and mud, and the motor looked like it was made out of rust. I cleaned the motor best I could but couldn’t get it to work. Decided to order a new t-case actuator for around $560, since I was hoping to get this thing fixed before this coming weekend, since we’re going to be doing some desert camping in Arizona.

I took the whole 4-hi gear housing cover off the new actuator, and put that on my truck in place of the old actuator cover with the rusted up motor (rather than dealing with soldering the motor I just swapped out the whole cover with motor, gears and everything). I tried a couple different ways of timing it, starting with the one suggested in the original post that initiated this whole thread. When that didn’t work (4-hi light kept flashing) I tried the “key on” method of timing it automatically, with the 4-hi gear housing cover taken off but wiring harness plugged in. Still got a flashing 4-hi light. Finally tried the timing recommended by DangTundra in the link above (previous comment in this thread). What I noticed when I timed it this way, is a whirring noise when I turn on the 4-hi switch, but the light keeps flashing. When I checked the front drive shaft, after turning the switch to 4-hi, the drive shaft no longer turns. So to me that says, the 4-hi t-case actuator is working, and the rod is pulled back to engage the front drive shaft. Right? But the 4-hi light is still flashing. So that makes me think that there may be something wrong with the front diff actuator?

I went to take a look at the front diff actuator, but I couldn’t find a screwdriver that would fit in there to open it up, and I tried to McGiver it with a wrench and a Phillips bit, but realized I was probably gonna end up just stripping the screws, so I let it be for the time being. The vent hose on the front diff actuator was nice and tight, so it didn’t have any obvious clues that it got wet in there.

I’m not a mechanic and this is my first newer truck (it’s a 2013 5.7 crew max) so I’m pretty ignorant about how computers and stuff like that work. I’m not getting any warning lights, just the flashing 4-hi light but that goes off when I turn the switch back to 2-hi. Is it possible that there’s a computer issue causing the the front diff actuator to not engage?

I’m pretty much done messing with the truck for a little while. We’re leaving for Arizona tomorrow so just gonna have to roll without 4x4 and hope it doesn’t thunderstorm on us when we’re in the middle of nowhere lol. Just figured I’d post on here in case anyone has any ideas of where to start once I get back and start messing with it again. The front diff actuator seems like an obvious place to check, but is there some other obvious things that I should check before I spend the time and effort trying to get that thing apart?

Much thanks to all who’ve contributed to sharing information on this thread, I read through the entire thread and gained a lot of helpful information to help me along the way. If the answers I’m looking for were already discussed and I just missed it, my bad. Any ideas or suggestions are appreciated.

 

try, activating the 4hi with the actuator not attached but still connected electrically and see if it rotates and hits the microswitch. As soon as it hits the swith, you'll be able to hear the front diff actuator engaging and your 4hi light should be solid. Keep in mind to have the 4lo connector connected as well, otherwise you'll get a blinking 4lo as soon as you turn the key and i dont believe the 4hi will try to engage.

 

I got the 4 wheel high. Now, but the 4 wheel low wont-work. What is the timing on the 4 wheel low

 

Connect it, turn the key with 2wd selected, 4lo will dial in itself, make sure the transmission is in neutral, push the rod all the way fwd, put the actuator in and test. If it doesn't work reset the actuator and turn the actuator manually a couple of degrees ( I cannot remember which direction) and try again. Took me a few tries to get it right.

 

Folks, I'm trying to fix my 2008 tundra which is stuck in 4h (but the 4lo light is flashing).

From the service manual (it says it's for 2009, but I think it's same for 2008), there is the following. Given the issues that I'm having, I think I should check the 2wd-4wd transfer shift actuator first. But which one is that? Is that the one closer to the ground or higher off the ground? Also, once I identify the correct one, does the rod being pushed in mean 2wd or 4wd? Also, once I open it up, what if the rod does not move (while transmission is in neutral of course)? My truck is currently with my mechanic, and I'm planning to take it back and try to DIY because the estimated repair was going to be 4 to 5 thousand dollars. I'm currently just doing some research, and imagining the possible scenarios.

 

I finally got my 4x4 working! I swapped the transfer case with one I got from a wrecked truck. Got tired of running circles around the problem

 

Your 4HI actuator is on the upper side of the transfer case and the 4LO actuator is closer to the ground. I can't remember for certain which position the rod is in for 2wd vs 4wd. You should be able to read the thread here and figure that out. Have you had the key on (engine not running) and cycled the 4wd switch? You should be able to hear the actuator at the transfer case make a whirring noise as it moves the rod. The actuator can also make a beeping noise if it isn't working, but mine never did that.

 

Hail Mary attempt here, I have not been able to find anyone who has found a replacement for just the micro limit switch. Does anyone have a supplier or pn for the micro limit switch? Failing that, anyone have an old housing lying around they want to sell with a good limit switch? I'm trying to avoid new or junkyard purchase of the whole actuator assy. Thanks.

Mathew

 

https://www.mcmaster.com/products/micro-switches/
https://www.electronicsurplus.com/switches/microswitches
https://www.we-online.com/en/components/products/em/switches/micro_switches

Good luck