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.ThanksThis 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.
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.What exactly does the big spring do that is under the big plastic gear?
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.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.
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: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.
I... don't... believe it.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.