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I've been having trouble the past few months getting my 01 in 4x4. Today it completely failed with the blinking 4 high light regardless of the button position. Hopefully the information here will help me fix it myself.
 

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I live in the mountains in Colorado and have used my 4WD frequently. Never had the slightest problem with it. A few months ago, my automatic transmission went out while I was in Arizona, and I had it rebuilt. The tranny seems fine now, but the 4WD has stopped working. Unfortunately I didn't try it right after the rebuild. I didn't try it until after I got it back to Colorado when the first snow storm hit a couple of months later, and then got nothing but the blinking light. I put it on a hoist, and all the wires, etc. had been reconnected. I haven't had the chance to try the "reversing" quick solution suggested above yet (the truck is now sitting in 2 feet of snow with little hope of moving it while 4WD is out). The truck is an '01 with 250,000 miles on it.

Anybody got any ideas that might be related to pulling and replacing the transmission?
 

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Re: Another 4WD Actuator Fix

This thread was a major help in running down my 4WD problems, thanks to all who posted.

About a month ago my 4WD light started flashing when I tried to disengage 4WD. 4WD Hi & 4WD Lo both worked but I had fits getting it out of 4WD.

I talked to two local shops about the problem, neither had ever come across a Tundra 4WD issue.

The root problem was the cracked vent tube, see #26, which allows water into the electrical housing. That water combines with the yellow grease to form a non-conductive crud over the concentric rings of the cover. No conduction, no motor, no 4WD Engage/Disengage. Many have referred to the rubber tube as a vacuum line, I could find no logic to suggest it's a vacuum line, no vacuum motor or piston anywhere. That said, I don't know why a vent is needed either.

If you're lucky you can remove the cover, clean off the crud from the concentric rings, reinstall and viola 4WD Engage/Disengage.

If you're unlucky you can remove the cover and the drive wheel will fall out, nothing holding it except friction, and your problems have just begun. I could not get the fine spline of the geared wheel inserted into the floating pinon gear.

The only solution I could come up with was to remove the pinon gear before installing the 4WD actuator assembly, bolt the 4WD actuator assembly to the transfer case, drop the pinon gear onto the small shaft spline at the same time aligning with the rack, then reinstalling the triangle cover.



In case you're wondering, the two switches drop into the two notches on the back side of the rack to provide position logic to the 4WD control computer in the engine bay. If they're not happy, the dash 4WD light will flash.

The official Toyota repair manual only mentions the 4WD actuator assembly, zero details. You are expected to replace the entire 4WD actuator assembly if problems.

Hope this helps someone.
I cleaned the gear case actuator because 4wd light was blinking but when I took the plastic cover off the plastic spring loaded gear as I call it fell out.Anyone explain where it is positioned when put back on or post pics.Thanks
 

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4 wheel drive actuator motor



The above shows the motor and pinion that drives the rod which actually shifts into/out of 4WD. There's a large clock spring in the wheel which prevent correct positioning relative to the conductors on the housing.


So, a bit of luck is required, otherwise known as trial and error.

Remove the pinion cover and pinion, reassemble the motor case, attach the motor to the transfer case, drop the pinion onto the shaft, replace the cover and pray. By some stroke of good fortune this worked for me the first time, may/not for you. Been 2-years so I'm a bit fuzzy.

All is not lost, for a mere $3000 P&L your Toyota dealer will drop the transfer case and replace everything. The drive motor assembly is not a "serviceable" part according to Toyota.

All this because of a cheap vent tube. Often called a vacuum tube, there is no vacuum involved, just a vent.

Have fun!!!
 

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hi thx for the reply I know its been awhile.I put the transfer case in 2wd and the front is not locked .I disconnected the battery to rest ECU.Only thing I don't know is the correct position of the large plastic gear with the contacts on it relative to being in 2wd when dropped back in to the actuator body.What exactly does the big spring do that is under the big plastic gear?
 

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What exactly does the big spring do that is under the big plastic gear?
It simply stores the energy of the shift when the long rod, the rack, won't move. You hear a clunk when the rod moves.

IIRC, it isn't that spring that's the issue, rather inserting the spline on the shaft into the pinion. The only way I could get the pinion on the shaft spline was via the procedure described above.

As to the position of the wheel, I suspect it doesn't matter and the electrical contacts sort that all out for you. Just a guess.
 

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Was just about to R&R the 4wd activators on the front diff and X-fer case when I saw the comment from the service writer, activate 4-hi, steer hard left or right, and before I could put it in reverse it clanked loudly and the light came on steady. I rolled it and could tell it was in 4wd. Disengaged and reengaged several times in neutral and was able to go to 4-lo. All this after almost two years of no 4wd.

Thank you TundraSolutions members.
You're the best.
Thanks for all your help guys and sharing what you've learned by trial and error. Just replaced my 2001 tired out Tundra with a shiny 2004 one with low KM's. However the previous owner must have been irresponsible in not engaging the 4x button often and found I had the dreaded blinking light. Jumped on the forums here and read all the posts on what y'all have tried and learned.
Gathered courage and finally climbed under this morning to try my luck. Unplugged and plugged in the terminals, removed the vacuum line to check for wear, used my heat gun and warmed up the actuator and ADD units (both front and transfer case) and gave them both a good-gentle but firm tap. Crossed my fingers and before driving and in park engaged the 4hi button. Placed it in reverse and turned hard right and left. TaaTaaaaaa, it instantly came on! SUCCESS!!
Took it down the road engaging 4hi and then into neutral for 4lo, switching it off and on multiple times. A slight noise first time into 4lo but nothing loud or clunky-just needed movement to release it. Working smoothly now.
Many thanks. Saving $$ and peace of mind was well worth reading through the many threads about 4x failures.
My simple rookie advice: don't be afraid to try some non-invasive attempts with some good advice from brothers who have been there.
Keep up the good work.
 

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Last night I was working in a field and turned on my 2001 Toyota Tundra's 4 WD.
Immediately both the Hi and Low 4 WD buttons began flashing as well as the display.
When I pushed the button 4WD would not engage and flashing would not stop flashing Hi Low 4WD.
I had no idea what was happened so I called a friend and he suggested disconnecting the battery terminal waiting 10 min & reconnecting. To make a long story short it continued flashing. This morning I called a transmission shop and spoke to the owner about what was happening. He said its the actuator motor just did one last week its common will cost $1000 for the motor and $500 labor for a total of about $1500. I then googled the question and joined discussion. I then printed out everyone's response and called another mechanic bringing your comments with me. The mechanic was receptive to this discussion. He tested the power and continuity of the actuator and plugs. He then told me to push the Hi and Low 4 WD button while he lightly tapped on the actuator with a hammer. Within 5-10 taps there was the old engaged sound and the light went out. The mechanic then told me lack of use. Make sure you drive at least 10 miles per month in 4 WD to keep everything working properly. He then told me to do the same with the air conditioner in winter and the heater in summer. Run them for 10 minutes a month or so. Thank you everyone. You ARE the greatest. Had I not come across your discussion I probably would have gone with the first mechanic's suggestion. THANK YOU !!!!!!!!!!!!!!!!!!
 

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i had the same problem and replaced the front actuator per the dealer at $450.00 and that worked for about 2 weeks until it started again...

the dealer could not find the problem and said the transfercase actuator might be it.

i then was going to replace the transfercase actuator until i found out the actuator was $1050.00 and required the transfer case to be removed and pulled apart at 12 hr labor for a grand total of $3500.00.

i took my tundra home and found a simple fix for mine, you can try this with yours it takes 15 mins.

i took the transfercase actuator cover off (3 bolts a vacuum line, and connector) and the actuator some how got water in it, looked like a bad o-ring to me, the contacts were rusted and not conducting power so i took 800 grit sandpaper and sanded the rust off, put some Dielectric grease on the contacts, and some black rtv on the cover.

i have had no problems with it after that.

also the front diff actuator is very similar (4 screws hold the cover on) the same fix can be done with this one as well..

i have some pic of the cover before and after.
nytrousboy - did you have to take the actuator assembly off to open of the cover and get a look at those electrical tracks or can you do that while under the vehicle without taking the transfer case off? Something is wrong with mine and they want $2500 to fix it :surprise:
 

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First my front drive shaft out put seal failed. My tundra puked all over my garage and I found this when I was running late for work. Replaced the seal. Now my 4HI is flashing and with my truck on jacks I've found I'm in 3WD front left is spinning. So I know the problem is T Case actuator. The actuator makes noise but the gears don't move. The actuator seems to have short shifted and has gotten lost on the T Case rod. Pulled it off and tore it apart. Filthy with 340k miles there is no grease left only crust. Everything is cleaned. The cap of the electromotor is supposed to have 4 magnets attached to the side. 1 has broken loose. Cleaned, filed, and epoxied back in place. Hoping I can get everything back together, on the proper point of the shaft, to place truck into 2WD.
 

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Adding something to the strange 4wd symptoms. I get the flashing light on the dash that everyone has described. However, I can get it to engage 4HI and 4LO if I unplug and plug the tcase sensors. I pulled them out and continuity check is fine. They both have about 60 ohms of resistance. Any suggestions?

 

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I've been fighting with my 01 4x4 blinking off and on. The contact on the transfer case actuator cap look great. I cleaned the factory grease off. I still have the blinking 4 hi light. I trimmed the vacuum hose and double checked my connecter. I need to tear into the front actuator now. Does any of you have any tips on how to get the Philips head screws off, and is there enough clearance to get the actuator cap off assuming that I can get the screws off? Also does anyone know where I can get pictures of the inside of the front actuator?
 

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I know this is going to sound lame but my brother in law works the service counter at a toyota dealership and he said they see this problem quite a bit. Their fix is to engage the 4 hi button in park, then when the light starts flashing put the truck in reverse on dry pavement and cut the wheel all the way to the right or left while backing out slowly.

It fixed my problem. He said for some reason if you do not use your 4 wheel drive regularly that the grease migrates in the mechanism (or something like that). Anyway it was a superquick easy fix for me and after trying to figure this out for about a month of crawling under my truck and tapping the ADD, I am happy to have this behind me.
I... don't... believe it.

This worked for me. Drove around on the mountain all day hunting. Put it in 2 wheel to come out and decided to go back in for firewood. Couldn't get back in to 4 wheel. Came home because of it. Read this and before digging into the actuator did as mentioned here, and it worked! Made my wife read it, only to get the standard eye roll and I just laughed and told her it worked. Unbelievable.
 

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Hi all,
Hope you can help this auto-know-nothing. I have an 04 4wd Tundra with a manual 4wd shifting mechanism. When I change the drive from H2 to H4 or L4 there is no indication of 4wd being engaged on the dash. I'm not sure if that's a sign that the indicator light is faulty or if the truck has remained in 2wd. Any input or a way to test if 4wd is actually engaged would be helpful. Thanks everyone.
 

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Corky, I'll chime in also to get this thread revived, since I'm having the same issues as others on here. If your truck is in 4wd and your turn your wheels on dry pavement, you can feel it bucking as the front wheels wanna go the way they are pointed and rear ones wanna go forward.
 

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Hello Everyone,

I have a 2001 Tundra and this is my first post because it's the first time I've had issues with the truck. My rear wheels were slipping on some ice pulling out of the grocery store, so I put the truck into 4wd and a massive clunk like I was hit from behind happened. I'd never heard that. It is weird because I live in Tahoe and we've had a record month for snow so the truck has been in and out of 4WD constantly.

I began searching the internet and have referenced this particular post many times. I tried knocking on the front diff actuator and transfer case actuator while my roommate went in and out of 4WD, I tried the slow reverse thing multiple times, etc.

I took the truck down to a friend in Reno who is an ace mechanic. We had a random issue with his Toyota software, unlucky timing, but he got under the Truck and immediately thought Ohhhh, this sucking noise your T-Case actuator is making is not right. If it was a good seal, it wouldn't be making the noise. Flash forward a few days, I listened to someone elses Tundra, and sure enough you just hear some mechanical type noises, but no real vacuum noises.

Prior to him saying that, I had already seen a rough looking end and had cut the hose and re-attached. He thought it still looked cracked, so he cut it back a bit more and reattached. Still no luck, sucking noise. I told him people from this forum were taking off the cover and I would do that and see what it looked like the next day.

So, I took off the main cover and it was flawless inside. He asked me to take off the little pot top with the spinning "motor" and I did that and it also looked flawless, but there are these little spring loaded wire brushes in side that are a major pain to get back in on the spindle and installed correctly.

I got them back on and when I put the actuator back on, now nothing, it doesn't even make noise. I took it back off and peaked inside with the hole cracked with a light and both wire brushes are right where they should be making contact with the spindle.

In removing the main cover a second time, my o-ring is now in 2 pieces, but it did look to be pretty OK the first time around. Upon investigating further when putting the main cover back on just so I can drive the truck in 2WD, the interior circular component with the 3 electrical contact points and the shaft out the back came out and a small amount of T-Case fluid came out. That part would not slide back in easily, but with some taps from a rubber mallet seemed to go in correctly and I put the cover back on.

Currently I have not started the truck to try 4WD to at least see if the system tried to work and made the sucking noise again to get back to where I started because I don't want to do any further damage, and I know it won't actually work because the O-ring is busted.

SO:

#1 - I looked on the Toyota Parts website, but didn't see the particular O-Ring listed. Anyone know a part number? Also, I broke 1 of the 3 bolts when installing as I didn't realize they had no end point.

#2 - This small amount of Transfer case fluid that came out I imagine isn't a major concern. Sounds like 1.2 Qts are in their and I did replace this fluid 25K miles ago so I'd imagine for the moment 1-2 oz's isn't a big deal?

#3 - Is there any concern with how I got that male spline component back into the female component where the small amount of fluid came out? Or if it went in, it should be fine?

#4 - What the heck is going on? The hose has been check, the interior of the actuator looked flawless, I feel like I removed a part that looked perfect and have most certainly made the situation worse at the current moment, but at the same time it did still seam like something was leaking when sucking.

Pictures attached.

I am no pro mechanic, but I like to mess with things and try to fix problems and can typically follow directions. I was afraid to mess with a $900 part as I know it always opens a can of worms, but a professional friend was pretty confident there was an issue with it, so I'd rather tinker vs. blindly spend $2000 to replace it. Sometimes I'm happy I got into it, sometimes 10 hours later with only backwards progress, not so much! Ha. Only one way to learn.

Thanks for any help. Much appreciated.
 

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Thanks for all the great suggestions on here guys. 02 Tundra Sp Edition. Same problem as most, 4 Hi light flashing, no 4 lo light even with pushing button numerous times. Up on the ramps and crawled underneath. Right away saw the rear actuator vent/vac tube unplugged. Ahhh perfect ....quick fix! Nope, no change. Figured with the tube being unplugged for who knows how long that maybe moisture in the actuator itself, removed cap (no broken bolts whew)! Tiny bit of moisture and could see the tell tale blue of corrosion on one of the fingers. Cleaned inside cap with a Dremel and some 180 grit emory on the fingers themselves reinstalled, started truck and no more light!! Gotta love it! Hell of a clunk on the first shift into 4 lo but fine after a few shifts in and out. Now to cancel my Monday morning shop appointment. Thanks again everyone!!
 

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2010 Tundra 5.7 Dbl Cab TRD 4Wheel Dr
Truck was in 2 wh dr most dash warning lites on solid, 4 hi 4 lo flash very quickly alternately not at same time. Transfer case actuator could be heard beeping and clicking. Eventually with fairly loud clunk comes out and goes back into 4 wheel (2 or 3 times) it is now in 2 wheel so I am leaving it. I put it in 4 wheel every couple weeks, did so about a week ago. Had truck since new has 85000 miles on it, never off road , completely stock. Tried the back up turning thing, and all other suggestions except battery disconnect. Any suggestions would be appreciated , thanks in advance.
 

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Hey guys.......I've got an 05 that I just bought. 4hi blinks, theres no 4lo light at all. I tried the whole putting it in park, shifting into 4hi, then cranking the wheels back and forth to attempt to bring the actuator up into play. No luck.

If I could get some better pics of what to look for as far as the actuators on the transfer case and the rear/front actuators that would be awesome.
 
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