transfer case issues

hey everyone- need some input on my son's '08 Tacoma (4.0, 6 spd).
so the problem is 4x4 hi/low, if you drop it into hi whether parked or rolling it does engage BUT the 4lo light begins blinking and you get the warning chime, no change if you move the selector to 4lo. it does not lock into low at all currently, previously it would eventually lock in then it eventually would come out if selector switch actuated and you just run it- you had almost no control over it really.
local shop we use for a lot of our work said they believed it was the ADD or another switch internal to the case (I forget- it was a while ago) and they said the most cost effective/simple repair is if we found a decently priced used case. i found one semi local ( large used atou parts place, very good reputation and we have always had good experiences with their gear) that had been ops checked and carries a 1 year warranty. we just swapped it all out and the problem persists- what do the Taco lords have for input?!
and since a picture get views- from last fall when he left it in neutral and the e-brake let go, i guess its a good thing i had a crusty old grader parked in my overflow driveway area and the transfer case drama was in the mix prior to this!

 

I'd start with voltage readings.
Once we know what "doesn't belong", we can guide you further.

We have a whole thread dedicated to the 4WD system.
If you can get us the voltage readings, it will help a lot.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

I've gone through 2 front actuators in a year, I wheel pretty hard, and they keep rusting up. I changed my rear thinking it the rear, and again it was the front changed and no problems engaging now

 

If they are rusting. They are getting water inside.
Have you inspected/replaced the breather tube on the actuator?
You might even reroute it yourself to see if that helps.

 

Thanks for chiming in guys! So out of curiosity have either of you seen symptoms like this when a front actuator has shit it’s pants? From what I’ve read it seems when those go out you don’t get 4hi or lo regardless of the dash indicator

 

Never seen your symptoms show up on a front actuator.
I’d suspect the switch or the transfer case actuator, not the front ADD actuator.

But the voltage checks will tell us where to look.

 

It could be either one of them, wouldn't hurt to check the vent hoses on the actuators.
I can throw some scenarios at my 4wd simulator when I get home and see if any match what yours is doing.

 

Trying to figure out how the front actuator would cause the 4LO light to flash?
Something’s getting signal when it isn’t supposed too.

 

There's multiple scenarios that would cause both lights to flash fast but the only scenario I can make the alarm sound is if I switch the switch to 4L without the Neutral signal, in that case the 4wd light goes solid and the 4Lo light flashes slowly and the alarm sounds.

So we may have a bad 4wd switch but I need a bit more info on the sequence of lights and switch operation.

 

Yeah. I was thinking switch.
But that’s a total guess with out know more.

 

Now maybe this is a stupid bit of input, but we did swap an entire transfer case. Therefore, all of the case mounted accessories went with it. I know it’s possible that we got a failed part on the new set up even though the shop claimed everything was 100%, but I wasn’t expecting the exact same discrepancy especially because it seems like a bit of an oddball if it was associated directly with the t case. And I’ll be honest I’m very mechanical, but I don’t mess with electrical. So I’m not gonna shoot any wires or do any of that right now, when it heads into the shop for inspection and a couple of other things, I’ll probably let them chase it down, and I will have to relay what the findings are. I was just hopeful that this was not as uncommon of a gripe as it seems and maybe there was someone with experience in this point in a direction and save a little bit of that time and headache with a shop

 

I hope they know what they are looking at and they don't just start winging parts at it like 90% of shops do because either they don't know any better or can't be bothered to do some actual diagnostics.

We can help you but you have to be willing to do some voltage checks, that's the only way this system can be properly diagnosed.

 

Yeah they’re a good shop and a small local one that I have a very long-term relationship with they’ve always treated us in our family and our business very well… Like I said, I’m not answering all electrical. This is a scenario where my time has value and the juice isn’t worth the squeeze for me to fight that right now

 

Ok good luck, hope it works out.

 

OP, please let us know what you find.

 

Good luck.

When you take it into the shop.
You might tell them about the link I posted in post #2
They are going to know why the 4LO flashes in 4H.
And the only way to know is to check the voltages at the 4WD ECM.
The 4WD ECU makes the light flash.