4WD Diagnosis

I’ll keep it short and sweet. When trying to get my 4WD to engage, 4 hi and lo just flash. Haven’t tried engaging in awhile, but recently now just 4 hi is flashing. Not engaged into 4 hi currently, still 2WD. All help is appreciated.

 

Have fun : https://www.tundras.com/threads/4wd-issues.119382/#post-3081795

Meanwhile, I never want to assume anyone has RTFM, but you can't shift into 4LO unless the following is true first:

• You've successfully shifted into 4HI and its LED is solid green.
• You're shifted to Neutral before tapping 4LO button
• 4LO LED has gone fully solid also

First thing to check, before hitting that troubleshooting, is to plug/unplug actuator harnesses and check the pins for any bent/corroded and no wiring in the harness is melted, then check actuator vent tube(s) for cracks/breach.

 

Just a simple question before you dive into diagnosing it…while in 4wd hi, did you put it in gear, drive forward, then reverse, then drive forward again? Sometimes it takes a little coaxing if you haven’t used it for a while.

 

Yes. It’s a pain to get in, if at all, and even worse to get out

 

Sounds like you need to open up the actuator and clean up the contacts.

 

This look like it’s supposed to be there? I l ow nothing about vacuum hoses so idk if it’s supposed to be some connector or if it was a half ass fix for the vacuum.

 

I think I found my culprit. @Jack McCarthy i think you were on the money.

 

Well I got good news, and I got bad news.

good news is I found the problem. My contacts were so eroded (top right ish of the actuator) that it’s down to the plastic.

Bad news is I’m going to have to replace that contact, which leads me into my next question. Can I buy individual contact rings? Or am I going to have to replace the actuator?

 

Cheapest option? Hit a junkyard. Snag a better cap. Or grab whole actuator.

Best bet will likely still have the rubber vent tube intact.

Actuator may be fine. New actuator is $$$$

 

Got it. Another question, if I screwed up the gears putting it back together, will hear any kind of grinding to diagnose that? Or will it be relatively silent.

 

Above my pay grade. I can give parts suggestions all day long

Everything I know is in that link posted above which is pretty much everything I’ve read on 4WD while here. And a video that covers disgnosing the cap you found to be faulty, that video had similar condition to yours but not as severe.

 

Got it. Thank you sir.

 

There are cheap aftermarket parts that quite frankly I would be tempted to buy:

$110 36410-34015 Transfer Case Motor Replacement for 2000-2006 Tundra, 2005-2017 Tacoma, 2010-2017 Toyota 4Runner 4WD 4-Wheel Drive 4x4 Transfer Case Shift Actuator Motor Transmission Actuator Assembly

https://www.amazon.com/36410-34015-...ransmission/dp/B0B5QGX7PQ?smid=A1BQU0OISMZCZS

Used from a local salvage yard if you have one, otherwise eBay

https://www.ebay.com/itm/266182585268

 

There’s a yard w two tundras in it, but it doesn’t say if either of them have 4wd. Gonna see if they’re open today and see if they’re 4wd. Fingers crossed.

 

Sending good juju holiday vibes that way

 

If you get one you might want to open it up and clean it. You know how to now! Get some dielectric grease (Autozone, or nearly anywhere else) and slather it generously inside. Pro Tip: Don't open the motor housing...you may never be able to re-assemble it

 

While you are there, make sure you grab the discontinued little parts like the washer nozzles. That way you have them for future. Especially the ones that look like this

Yes @shifty` , I know that I need to finish the hood. Get out of my head

 

I mad the motor housing mistake last night and by the skin of my teeth and with the help of my wife I get it back together. Somehow. A neighbor loaned me some grease.

 

Pleased to announce 4wd hi/lo now shifts with the change of a new salvage cap. Only thing now is the 4wd light won’t stop flashing or being solid, which I imagine is a connection issue

 

Definitely check wiring, but give some more details on things you tried and results (flashing/solid/off). Maybe something will jump out.

Flashing usually indicates it’s in between states IIRC. Off means not engaged. Solid means fully engaged. I’d be curious to know when it thinks it’s engaged for not engaged.

 

It flashes for maybe 30 seconds and then goes back to solid. It will be solid for both engaged and not. It turns off very briefly, maybe 10 seconds, when I go out of it, then starts flashing again. I know this bc I took it around the neighborhood, I know I was engage as I could not make tight turns as well as I could hear it engage. I knew I was disengaged by the same turn test.
Another thing happen as I got home. I turned the truck off, and back on just to see, and it displayed lo. Hit 4hi, low went away replaced by a flashing 4 hi.

 

I feel bad I can never remember well enough m others have dealt with. But you mentioned getting into something earlier and hoped you didn’t f anything up. But a few people here have posted tidbits about how they verified all was lining up and engaging correctly and getting things engaging. Based on what you’re seeing light-wise, it almost sounds like the system can’t sense where it’s at, speaking to the 4WD ECU in the passenger kick panel if IIRC. But I don’t know the particulars about how the ECU “senses” everything.

You know where on here to find a copy of the FSM, right? May help you out.

 

FSM? If you mean the owners manual, yes I have it in my glove box. I’m going to my mechanic friends house tonight and maybe we can use his code reader and see if the truck throws any codes.

 

Ugh, I found my vent tube off earlier this summer. I suspect I got crud in that mechanism as well, but it seems to be working ok for now. That video helps. It does mention disconnecting the battery terminals to reset the computer. Can't hurt at this point.

 

FSM = Field Service Manual

 

I’ll give that a whirl. How long should
I have it off for?

 

@shifty` i do not have one. That I’m aware of. I’ll double check

 

@BobbyRaids Probably around 15 minutes. FSM is available online, else its a big 3 book set. I bet the link is in the 1st gen sticky section.

 

Download link is in the 4th/5th paragraph of this thread: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

 

10 minutes is the default standard across most vehicles. Remove the nev batt cable specifically.