Flashing 4x4 and 4LO - diagnosis help, 2008 SR5

Yesterday I selected 4x4 while rolling through mud. As the title indicates what i got was NOT 4x4 but a light show instead. Rip-off, right? Anywho...

Today I got under the truck to what i thought might be the culprit. That little box on the driver's side of the t-case. First thing i noticed was a cracked and fallen-off vacuum line that attaches to the nipple on the plastic case of the actuator - or what i think is an actutator. I trimmed the vac line and re-installed it. Tested out the truck - still flashy-flashy.

Back in the cab I removed the 4x4 dash switch and found power to the appropriate wires based on where the switch was rotated.

Back under the truck i set to take off the actuator - or what i think is the actuator. Pulling off the plug, i found the connections seemed corrosion-free (but they were not. I thought it was grease, but scroll down...) though a solid tablespoon or so of water was inside the cap.




While my tool-hander and light-shiner-oner dried the cap (to reminisce for when i had young kids helping, I yelled at her for shaking the damn light!) I double-checked everything i Could. The little sprocket-looking thing looked clean and undamaged; yellow grease abounds therein. I yanked on it a second because I yank on things, and it popped out a second and clean gear oil drizzled.

Running my multimeter i found power across the plug



Re-plugged and all that - still getting the flashing lights. I found a few threads on the forum but fewer solutions - one was "The dealer said there was a plug behind the radiator unplugged". Not a ton of help. Then i found the 'how to trouble-shoot the actuator' so am pretty convinced that front piece needs help/soldiering.


Next I will go to the actuator at the front diff to see if that actuator is actuating anything at all, actually.

More to follow. Opinions welcomed.

 

Definitely sounds like an actuator problem, unfortunately it’s usually on the front diff that goes bad and it’s a pain in the ass

 

If you have enough time.
Most of the diagnoses information can be found here.

https://www.tacomaworld.com/threads/4wd-system-help-and-information.696298/

Good luck

 

Thank you - thats one of the threads im reading. I have the ADD out, but 3 of the screws, like my exwife, want only to strip and not do what they should be doing. I have them soaking in PB Blaster now, hoping I can get 'em sorted somehow. Or it's buy a new ADD, which I will preemptively solder.

 

update...but pics later.

I removed the ADD, the connections looked great! I soldered anyway, re-installed and there's no change; things still flashing. I've removed the neg cable overnight and will hook it up tomorrow to see what i see. After this, do I bite the bullet and take it to a dealer?

 

You could take it to the dealership.
These problems are hard to figure out.
It can be done, but it takes a lot of testing.
The dealership will likely be expensive, but you won’t have to do all the diag. work.

In the link above I posted.
You will find these helpful diagnostic charts.
The information is there, but there a lot to diagnosing what the real problem is.

https://www.tacomaworld.com/threads/4x4-problem-i-cant-resolve.575092/#post-19056025

https://www.tacomaworld.com/threads...-case-or-diff-actuators.695818/#post-24612674

 

thank you. the charts and diagrams...i am not sure how to make sense of a lot of them. May have to bite the bullet.

 

Looking at that cap pic again, that's corrosion isnt it? inside the cap along the silver swirly bits? That could be the issue right there. yeah?

 

and this morning the truck is stuck in 4x4. I restarted the truck while the selector was in 4H. No blinky 4Lo!! woo! except when i selected 2H they both started flashing. going to try to clean that cap; also shopping for a new t-case actuator

 

Okay - here's the whole story...

Last night my girlfriend and i removed the A.D.D. Bottom-line-up-front? Get you a tiny girl with tiny hands for the upper left bolt on the ADD. Yeah. Frustrating with normal adult-sized mitts. She IS a legal adult...but not-quite 4'11" tall...so...yeah.


After the bolts are removed, one needs to finagle the piece just a bit to get it to clear the bars and supports - but it's not difficult.

(not her hand; adult-sized hand for scale)



I sprayed the five screws with PBBlaster and let it sit an hour. Two screws came out - the rest started to strip. Deciding I needed to get this thing apart I took one of the screws to Lowes and found these to be a perfect match - note, i've switched to bolts and lock washers. MUCH better in the case i have to remove this some day.

Replacement bolts, with part number, but i neglected to get a pic of the box closed-up. But the bolt heads are slightly smaller than the previous screw-heads so everything fits perfect. Suggest not wasting time on the screws. Drill them out at the first sign of being stuck. On the right, you'll see the new bolt next to the old screw (OldScrew was my nickname in college).



Okay - opening the case, everything looked spotless. no gaps in the prongs but I decided to solder them anyway. So, i think in my 48 years this may be the first or second time i've soldered and that inexperience may show up.





I placed two small dabs of red gasket maker along the rubber gasket in the case/cover and and cleaned the mating surfaces of the unit (hehe...unit) and the dif/axle place where it gets inserted (snicker...). Once I got things back together, my aforementioned girlfriend used her strong tiny hands to get that top left bolt for me. Having her there was invaluable.

Back in the truck with things plugged in and...........................


Nothing. No change. Truck still f'd up.

This morning I found a video where a guy walked the viewer through operation of the Transfer case actuator. He also did the ADD fix to no avail. After watching that, I ordered a replacement TCase - Amazon, $185...well, 168 but then the state of Oklahoma demands tribute, so 185.

$101 36410-34015 Transfer Case Shift Actuator Replacement for Toyota 14-19 4Runner, 05-15 Tacoma, 00-06 Tundra 4WD 3641034015 NICEKE

https://www.amazon.com/Compatible-T...r+case+shifter+actuator&qid=1625437357&sr=8-5

The guy in the vid mentioned he tried to clean out the cap from his old Actuator to no avail. But because i needed to get somewhere and this is my only car at the moment, I pulled the t-case actuator cap off (3 10mm bolts and one plug).

I wiped out the grease and found this staring back at me. Note the top ring with corrosion.



After about 10 minutes with 150 grit, i got it down to this - but you can see how pitted that bar is now.




Before I buttoned-up the thing i cleaned the three little 'fingers' and bent them to be a bit more erect before I replaced the cap plugged it in....and got into the driver's seat...turned the key....and....





BOOM. Worked. Perfect. It worked.

I'm still keeping my order of the replacement part however, as the scoring in that top ring bothers me. I am not going to replace the entire actuator, but instead just that cap.

 

Nice work.

Thanks for the update.
The alternative bolts is good information.
Thanks for the part #

 

Excellent! Some people have soldered more material onto that trace with some success. Grease her up good before you put the new one in. I'm not sure what kind of grease is recommended, but it'll help keep any moisture away from the contacts.

Good write up!