4x4 Issues

Alright gents, I know there are tons of post about 3rd gen actuator issues but I have not been able to find a solution for trucks issues.
To begin, I went to lock my truck in 4lo and it rolled back a little as it went into 4x4 and made a high pitch grind. After not being able to get it out of 4lo in reverse and neutral and so forth I got it out of the woods and at the house. Next I began removing the transfer case actuator to manually put it in 2wd to drive it to Toyota. This then left me with a blinking 4x4 light. After Toyota told me the transfer case actuator motor was shorted and gave me a $2,400 estimate I took the keys and left. Next I removed it again and tested the motor and it ran perfectly so I re installed it with the t case in 2wd. With it still not working I put 12V on the ADD to manual unlock the front end to try and match both actuators. After doing this i turned the truck on to test it but now the truck is giving me the 2wd-4wd mode change failure notification. Please please please help if you have encountered this issue.
Sorry for the long post

 

The ADD actuator is pretty easy, esp if you need to manually move it. The T case actuator is different and it is timed to the fork position. I believe someone has a thread here about retiming it without tearing down the T case, which is the Toyota method.

For other 4WD actuator diag and such, @BigWhiteTRD and @lapoltba have that stuff down cold and can help you out.


Good job getting it to where you have it for now.

 

I’m a bit unclear on what happened. Was it rolling backwards when shifting from 2hi to 4hi or from 4hi to 4lo? It’s ok to shift 2hi to 4hi when moving but not 4hi to 4lo. In fact it has always refused to shift between 4lo and 4hi when I am moving

At least with the 6mt, I also have to push the clutch all the way to floor to shift between 4lo and 4hi. My memory may fail me, but I think the auto must be in neutral.

How many times have you shifted in between 4lo and 4hi before this?

 

I was in neutral at the time but my foot slipped off the brake while rolling down hill and shifting between high and low. That’s when I heard the grind. It then locked in low and would not come out. Thank yall

 

There is alot to unpack in your description.

So there is no need to do 'timing' the Front ADD actuator vs the transfer case actuator. It doesnt matter if two actuators are in inconsistent positions (as long as each actuator is healthy) or even in mid positions; when you turn the key on the truck will move each actuator to the commanded position.

That said, the timing of both actuators can be messed up (internal to each the actuator).

It would help alot if we knew what actual codes were originally thrown. Currently its quite possible that there are several codes from the rework are stored.
ASSUMING there is nothing actually broken, its possible that either/both actuator now has issues. (its also possible that there is something broken, something shorted, etc. Its hard to troubleshoot what is wrong because there is so much going on here)

The forward (ADD) actuator can be manually driven (using voltage applied manually) too far in either direction, into a feedback-invalid position. If there is nothing wrong, but the actuator has been overdriven manually, you will need to drive the ADD to a mid position and then just reconnect.

The transfer actuator timing can be very much fouled up internally, assuming there is not also something broken.

The best instructions for transfer actuator timing I have found is the video in the first post here
https://www.tacomaworld.com/threads/4wd-actuator-troubleshooting-transfer-case-and-add.578262/

Other than this timing, the actuators/wiring would be evaluated with either ohmmeter or techstream to determine where the likely issue is.

 

Thank you so much for the info! How do you know the ADD is in the mid position.

 

That sucks. I've tried to get in and out of low range while rolling at less than 2mph. It never worked without a grind. For my Taco, I need to be stopped for sure. I couldn't imaging slipping off the pedal.

Hopefully you can get it sorted without new parts.

 

I had that happen to a friend and it sounded like a spoon in a garbage disposal and he ended up needing a whole new t case. Best of luck getting it all sorted out and hopefully it's as simple as getting everything all synced up.

 

You could check with an ohmmeter.
The way I do it is:

Apply ~6v to the actuator in alternating directions and get a mental feel for how long it takes the actuator to travel before it changes sound. Final time, just apply voltage for approximately half the time it takes to do the full travel.

 

Thank you so much BigWhiteTRD! I’m going to try it out tonight and see if I cannot get it all sorted out. Last question, while I am doing the work I would like to replace the Transfer Case Actuator O-Ring. Does anyone know the size or part number? I would like to pick one up on the way home today. Thanks again Gents.

 

The O ring that interfaces between the actuator and the t-case?

I THINK its 9030128013
(aka 90301-28013)

But I make no guarantee...

 

Thank you so much gents the front diff ADD was over driven! Adjusted it to the halfway point and all issues are fixed!!

 

That's great to hear.

 

NICE

first time I did that, I thought I had totally fckd the truck...