4wd Grinding and not moving

2017 Tacoma TRD. with 3.5 and automatic
When I turn on 4wd (4hi) (this happens whether in park, neutral or drive. Stopped or moving. Not turning). the 4wd light just flashes. And I lose power to the wheels. The truck will not move. It just makes a grinding noise, like gears grinding.
If I switch it back to 2wd, nothing changes. Light continues to flash and still makes the same grinding noise. The grinding noise happens no matter where the shifter is, but is definitely louder in Drive or reverse.
If I completely turn the key all the way off (after putting it in 2wd) then restart, it will go in to gear and drive again. the 4wd light continues to flash for a couple minutes, then goes out.

I cant find info online with someone explaining a similar scenario.
Not sure if it is the transfer case actuator, Differential actuator, or something worse like bad transfer case.
Any info is appreciated

 

If I were to guess, I'd say it's the transfer case actuator since you're not able to get back into 2WD easily. How often do you use 4WD and how many miles are on the truck?

 

I was worried about transfer case so I drive it in 4wd every 3-4 weeks for a couple miles as someone had suggested

 

74k miles
just got the truck. It was my first attempt using 4wd

 

It sounds like the 4WD system may have been neglected. It is one of those “use it or lose it” things. If you don’t engage it and exercise the actuators and diff occasionally, it might not work properly after a few years. This is why it’s recommended to engage it once every month or so. Have you taken it to get looked at by anyone yet?

 

I have not taken it to anyone. I do all my own work. Just new to this model. Looking for some insight.
I found schematics, tables, and connector pinouts for both actuators. testing those today.

 

Sorry, I guess you missed it on the test drive. Good luck. At least 2wd works

 

no. I didnt miss it.
It was known issue. I chose to purchase anyway. It was a screaming deal. I will fix it. There is nothing I can't fix.

 

Are you saying that after you attempt to transition from 2HI to 4HI that applying the throttle pedal causes the engine RPM to rise without causing any forward momentum... as if the engine is disconnected from the rear drivetrain? If so, my first guess is that the transfer case has a major mechanical failure. I do not think a actuator failure could cause a disconnect with the rear drivetrain. CAVEAT: I have no experience diagnosing such an issue, but I have experienced 2Hi => 4HI transition failure without any grinding noises or loss of forward movement.

 

yes gudujarlson, that's exactly what is happening. I also fear that it is a major mechanical failure in the transfer case. I was unsure if there could be a condition, where the transfer case actuator would cause an issue like that. Well, at least I was hoping it could be an actuator. Or at the very least I was hoping someone on here might have experienced the same issue and could save me some troubleshooting time.
I also have no experience with this system. It is my first 3rd gen Tacoma.

 

Hows the transfer case oil look?
TRD sport or offroad?
maybe not related- but the crawl control makes that heart-dropping grinding sound also.

 

Sport. Does not have Crawl Control
havnt looked at transfer case oil. yet. Im almost there.

 

Oil is almost never the immediate problem, despite the fact that it is offered as a possible cause in every thread like this one. An engine for sure and likely a transfer case can run for a long time with no oil, but it will drastically reduce its lifespan. Once its lifespan is over, new oil will not help.

 

True, but if its a major mechanical failure, there may be some sort of signs in the oil, like metallic shavings/pieces from the grinding noise. its going to have to be drained anyways

 

I'm thinking if the transfer case or actuator is/was toast, the "turn-it-off, restart fix" wouldn't work. I also think that if it was the transfer case itself, (failure) everything would be gone. It sounds like it's the lack of exercise (use) issue. Try this: sit in the driveway and shift through the sequence (2H-4H-4L) and back several times. Move it down the driveway a few feet in each setting if you can. See if it gets better. Don't let it grind away: do the key fix. IMO: the flashing light eventually clearing and back to normal is a good sign. Positive note is that you have some on-board diagnostics on the 3rd gen system.

There are also very knowledgeable folks on the Toyota 4x4 systems in here that will likely chime in. I do the above procedure a couple of times per month and you'd be surprised how much better the last shifts are than the first couple: Quicker and less noise and clunk-sound drama. (I never experiment with, or exercise "4L" when I'm away from home or civilization. Driveway only.

 

Toast thus the screaming deal. Good luck.

 

This wasn’t a salvaged truck by chance?

 

2HI to 4HI shift shouldn't be able to disconnect the rear output. But the range sleeve between hi and lo can put you in neutral. Interesting problem, keep us up to date.

 

Sorry, I made a snap judgement that you were suggesting new oil or a different brand of oil might fix the problem

 

Trucks a 17, screaming deal or not this and other issues are more than likely going to occur if you are not the original owner and do not know what preventative maintenance was done.

If no voltage a new transfer case is most probable here