How To Trouble Shoot 4x4 Actuator

it shares a tube for financial reasons. Real estate is expensive these days. For why it needs one, it’s an enclosed area with no fresh air. In theory it’s not needed but helps. It’s a fresh air inlet more than a vent and it helps to keep parts moving. If water gets in you’re screwed.

 

I've read through this entire 40-page thread (in parts, over the last week or two) and don't recall seeing any serious discussion about the best choice(s) for replacing the breather tubes (both actuators, transfer & ADD). Seems like a majority of early failures are caused by water/dirt intrusion & upgrading to more-robust tubing would prevent these. Looks to me like the stock/OEM tubes aren't the correct material for long-term use since they tend to crack easily.

What's the best type of tubing to use? Maybe viton material? Does anyone know the exact specs (O.D./I.D.) on the tubing? Has anyone put on aftermarket miniature hose clamps to keep the tubing from slipping off the friction-fit nipples?

This is the hose on my 2014 V6 6MT TRD OR at 63K miles, most of those highway miles on mild, salt-free California highways, + maybe 1K miles on dirt roads / light off-road use.

 

I haven’t any idea. But those of us with Automatic Transmission are going to have a hard time replacing the hose for the Transfer case. It ties into the trans breather and is on top of the transmission. Definitely doesn’t look easy to get to.

 

i replaced mine with silicon vacuum tubing. Don’t remember the size but maybe measure the old tubing, I believe I got from trail gear. A hose clamp isn’t necessary. It doesn’t operate at pressure so a barbed fit is plenty sufficient to keep the elements out.
https://trail-gear.com/drivetrain/engine/components-misc-kits/silicone-vacuum-hose-10-roll.html

 

The hose for the transfer case ADD is more prone to cracking/splitting IMO because of the tight angle the hose is at. What I did on mine was to cut out the bad end and added a right angle adapter with a 1” section of vacuum line to replace what I removed. It takes the pressure off the old hose so it’s not going to split on you nearly as quickly. Put a small zip tie around the old hose if you’re concerned about it not being brand new rubber.

I checked every other hose I could, especially the front ADD, and everything looks good. I’m pretty impressed with the longevity of the rubber components on these vehicles.

 

Aloha! Requesting some assistance please.

Working on my friend’s 2008 Tacoma with manual transmission. Truck has blinking 4wd and 4lo lights. Truck does not go in 4wd. I’ve tested both the ADD and T-Case actuator with a 12v battery and the motors work.

I cleaned, soldered, and applied lithium grease to the ADD. Moved the locking sleeve to the driver side when the ADD was reinstalled. Didn’t fix the blinking 4wd and 4lo lights. Also didn’t hear the ADD’s motor turn when attempting to turn the selector to any 4wd positions.

Cleaned, regreased, and clocked the t-case actuator. Spline was all the way down when I removed and reinstalled the actuator. Also checked both pressure switches and they still had the detent. Both the 4wd and 4lo lights turned off. However, the lights returned with I attempted to go in 4wd. Didn’t hear the ADD motor turn.

Does the ADD motor not engage if there’s a problem with the t-case actuator?

 

The 4wd ECU won't engage the ADD until the transfer case has completed it's shift into 4H and it sees those limit switches in the correct positions for 4H, same thing going into 2wd the transfer case always completes it's shift first.

Did you get the Transfer Case Actuator timed correcly when you reinstalled it?

Limit switch voltages can be checked at the 4wd ECU or the actuators.

Charts, voltages, sequence of operation, diagrams, and more in the thread below.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Thats on my list of things to do this summer is to replace the ADD soft lines. I have some 1/8" ID (I think) parts store vacuum line. Not sure if its the right choice, but its all I could find. Im going to try and do both rubber lines between the ADD and the breather in the engine bay.

 

Thank you for the assistance and reference!!! Will read up on it.

I seated the long pin on top of the dead space pictured. Is that the correct position or should the pin contact the trace upon seating?

 

I'll take a closer look when I get time but the contacts need to be lined up in the correct position for where the shift fork is in the transfer case after the housing is installed if that makes sense.
There's a picture of the cover with the contact positions overlaid on it in the thread I posted.

 

Thanks again! There's a small red circle on the attached pic where I lined up the contacts. I eyeballed it so that my be an issue.

 

Yea I checked that is the 2H position but do you have the transfer case selector rod in 2H (fully in)?

 

I believe you might be able to use a voltage meter to see if it’s timed correctly for 2WD?
In @Dm93 link you will see this picture.
Pin #5 should only have continuity with pin #4 in 2WD. And NOT #3 & #6.

 

He had the actuator off the transfer case though, in that case the position of the transfer case Must match the position of the switch wiper when it is reassembled or it will not work properly.

 

Yeah, like you said. Rod pressed all the way in.
I hate to even think about the day I will have to “look at” mine.
If I ever do, I will definitely take a bunch of picture.

Here is to NOT having to

 

Keep the vent hoses on the actuators in good shape and attached and use it regularly and there's minimal risk of issues.

 

They look ok. They aren’t cracked. But they definitely feel “hard”.
Probably need to address them before long.

 

Thank you again @Dm93! Your diagrams , charts and spreadsheets were money!!! I'm hoping the rod was all the way in. I pressed the rod as far in as I could with a large pry bar, i didn't see any notches on the rod to indicate it was further out than 2wd, and the wiper was set to 2wd when I reassembled. I only tested in cabin (the 4wd ECU). Please see my results. Any idea of what the issue might be just from looking at the spreadsheet? I'll continue on tomorrow to test the transfer case actuator.


Thank you @TnShooter! I'll try that tomorrow!

 

I'd want to backprobe TL1 (Pin 5 Blue/Yellow) at the Transfer Case Actuator and see if you also have 12v there in 2H, if you do then you need to check Pin 4 (White/Black) (should be less than 100mV, If it's 12V you have a broken ground wire or bad ground), if the ground is good you have a problem in the actuator (or a spread terminal in the plug), if you don't you have a broken wire or bad connection between the 4wd ECU and Transfer case actuator.

 

With everything across the board reading high I wonder if there is an issue with the GND connection?

The ADD readings make sense because it would not have attempted to engage