'96 Tacoma 4X4 Auto - Sticking Actuator

[kennyyoung]

Hey guys, my 4X4 has the push button style 4WD system and it wont engage. I crawled under the truck and the actuator just clicks when the 4WD button is pushed..... as I have someone push the button, the click sometimes gets louder and every now and then I hear the motor trying to kick in as I tap it with a hammer. I believe the actuator is sticking due to lack of use over the summer months. Does anyone know how I can get it to free up? I pulled a triangular plate off the side of the actuator to expose a cog and the shaft that engages the 4X4, but there isnt much to be done there. I want to try and take the cap shaped (motor/solenoid...what ever it is) off the actuator, to see if I can do anything there (this thing gets really hot when the 4WD button is pushed over and over again.....should it be heating up like that?). Is it safe to remove this without anything flying out at me, can I take the 3 screws out remove the cap and be able to replace it just as easy? Any info on this would be greatly appreciated!!! Thanks!!!!

[4x4CPOSEADOG]

Originally Posted by kennyyoung

Hey guys, my 4X4 has the push button style 4WD system and it wont engage. I crawled under the truck and the actuator just clicks when the 4WD button is pushed..... as I have someone push the button, the click sometimes gets louder and every now and then I hear the motor trying to kick in as I tap it with a hammer. I believe the actuator is sticking due to lack of use over the summer months. Does anyone know how I can get it to free up? I pulled a triangular plate off the side of the actuator to expose a cog and the shaft that engages the 4X4, but there isnt much to be done there. I want to try and take the cap shaped (motor/solenoid...what ever it is) off the actuator, to see if I can do anything there (this thing gets really hot when the 4WD button is pushed over and over again.....should it be heating up like that?). Is it safe to remove this without anything flying out at me, can I take the 3 screws out remove the cap and be able to replace it just as easy? Any info on this would be greatly appreciated!!! Thanks!!!!

You need to drive the truck on a sandy or gravel road making a circular or figure 8 until you hear the actuator to lock the center diff lock. It will be easy for the diff lock to lock if it is moving and not stationary. And if you have done what I suggested and still is not working, then you have to take that actuator and rebuilt it. That actuator cost a lot of money at the stealership. Good luck.

[PreRunnin41]

i belive the OP is refering to the transfer case actuator not the RR DIFF LOCK.

[kennyyoung]

Here is a few pictures of what I am dealing with.... if any one can suggest what I could be trying, please feel free to do so.... all comments are appreciated!!!



Here is the actuator...do anyone know if its safe to take off the actuator motor held on by 3 screws or if it will actually help me or not?

Here is the motor I think I want to remove (brown cap like object at the top of the picture).


I have been tapping the actuator trying to free it up while someone continues to push the button....at times it clicks louder and sometimes you can hear the motor trying to engage. I'm hoping its just a little rusty and sticking from lack of use over the summer months?

[PreRunnin41]

i have the J shifter so i'm not much help. but have you checked all vac hoses? Just a thought that it may not be pulling hard enough from loss of suction?

[kennyyoung]

I have checked some of the vacuum lines , but I'm not really sure which ones to check.... there are so many of them as you may be able to tell from one of my pictures.

[4x4CPOSEADOG]

Originally Posted by kennyyoung

Hey guys, my 4X4 has the push button style 4WD system and it wont engage. I crawled under the truck and the actuator just clicks when the 4WD button is pushed..... as I have someone push the button, the click sometimes gets louder and every now and then I hear the motor trying to kick in as I tap it with a hammer. I believe the actuator is sticking due to lack of use over the summer months. Does anyone know how I can get it to free up? I pulled a triangular plate off the side of the actuator to expose a cog and the shaft that engages the 4X4, but there isnt much to be done there. I want to try and take the cap shaped (motor/solenoid...what ever it is) off the actuator, to see if I can do anything there (this thing gets really hot when the 4WD button is pushed over and over again.....should it be heating up like that?). Is it safe to remove this without anything flying out at me, can I take the 3 screws out remove the cap and be able to replace it just as easy? Any info on this would be greatly appreciated!!! Thanks!!!!

When you pushed the button, do you see the center diff lock light on the instrument panel blinking or it is solid light?

Originally Posted by PreRunnin41

i belive the OP is refering to the transfer case actuator not the RR DIFF LOCK.

I understand he is talking about the tranfer case diff lock actuator, the reason I would like for him to drive it like I mentioned is to make sure the actuator works and not the diff lock position sensor switch. The actuator may be working but wont register on the instrument panel due to faulty position sensor switch.

[kennyyoung]

When I push the 4WD button the light does not light up..... the only time I can get it to blink is when I start the truck with the button already in, then it blinks and sounds a buzzer until I push the button to the out position? Any ideas why? Oh yeah, I tried driving like you said in the figure 8 and stuff... no change. I got as funny feeling the actuator is sticking from lack of use over the summer months.

[4x4CPOSEADOG]

Originally Posted by kennyyoung

When I push the 4WD button the light does not light up..... the only time I can get it to blink is when I start the truck with the button already in, then it blinks and sounds a buzzer until I push the button to the out position? Any ideas why? Oh yeah, I tried driving like you said in the figure 8 and stuff... no change. I got as funny feeling the actuator is sticking from lack of use over the summer months.

Let do this, first you need to remove the position sensor (red arrow), clean it up and make sure the ball bearing at the end moves freely. Install it back and will see what happen. If that does cure the problem, the next step is to take the housing off of the diff lock assembly to make sure the springs are not corroded.

[PreRunnin41]

For the love of god please use PB blaster before you get to wrenching! I dont want to hear about broken bolts! Good Luck!

[kennyyoung]

Oh my God.... thank you for a suggestion and pointing out on my pictures what I am dealing with. This is exactly what I am needing. So when I remove the position sensor, nothing will spring out at me or anything will it? Also, like you said if that doesnt solve the problem, I will have to take the housing off the diff lock assembly...will anythig spring out at me here ....this is what you have pointed out in my picture right? I just thought of something.... if thats only a breather hose on the actuator, can I spray some lube in there first instead of taking it apart? I really appreciate your help!!!
Oh, by the way, by looking at my pictures can you tell if my actuator is vacuum operated or not? I have no idea!!! Also, do you know if it safe to take off the actuator motor without anything springing out at me as well (I have a fear of things popping apart and pieces going everywhere) maybe I can clean this up as well???

[kennyyoung]

Here is another picture of my actuator.... this is of the triangular plate (top right hand side with the orange gasket showing) I removed to take a look at the cog and shaft ....in the center if the cog it looks like a Torx bit would fit in to turn it, but its much finer (it probably has 16 points.... is there such a socket?). I am thinking that its there for the reason of turning the cog and moving the shaft manually. I guess I would have to remove the motor on the other side of the actuator to let it freely move. How hard is it to take off the motor and put it back on....is it just a cog on the end of it entering into the actuator?
Oh by the way, thanks PreRunnin41 for reminding me to use PB blaster....lol....I dont need anymore problems!!!

[taroy1]

I'm waiting anxiously for the outcome. I have exactly the same symptoms with my '95 Tacoma. I can't seem to find much time to tinker with the actuator for a few weeks.

[kennyyoung]

I'm having a hard time to find the time as well, by the time I get off work ... its dark!!! Have you done anything with your actuator at all yet?

[taroy1]

To date, I've only tried tapping on it with a hammer while my daughter cycled the switch. The motor does run briefly with some clicking. Unlike some who have reported doing this, I could never get it to engage, not even intermittently.

I found this page about an actuator problem on an '02. I haven't fully read through it yet but the part looks different than ours so it likely won't apply.

http://www.worldpath.net/~thompson/tacoma/locker.htm

[kennyyoung]

Yes, I came across this page earlier this evening, it does give me a better understanding on how the actuator works, but it is a little different from ours.....does your look exactly like mine? Are you driving a '95 Tacoma 4x4 automatic? Do you have the factory service manual, it is available online!!!

[taroy1]

Mine is a '95 Tacoma 4x4 (1st model year) with manual transmission. I do have printed factory service manuals purchased used on eBay. Looks the same as what you found online. The little picture of the actuator therein isn't very helpful and doesn't give any clues to its internals. Here's an interesting thread going over the diagnostic procedure. Once there, click "show more" to see the bulk of it.

http://www.justanswer.com/questions/...oma-4x4-reason

[taroy1]

Originally Posted by taroy1

I found this page about an actuator problem on an '02...

Well, that's certainly different than ours and is on the rear differential, not the transfer case.

[kennyyoung]

So your truck has a lever to engage the 4x4 does it..... mine is the push button on the shifter. So, I would imagine that our set up is a little different , but maybe they are similiar enough to have the same problem/fix though. The reason the factory service manual doesnt give any information on the internals of the actuator is because it is considered a non servicable part. Does your actuator look exactly like mine?

[taroy1]

Mine is just like yours with a push button on the high/low shifter. Your pictures under the truck look exactly the same as mine. I even printed one and took it outside in the dark with a flashlight to compare. I think they're all the same at least up through the '99 model year.

[kennyyoung]

Ok then, we definitely have a common interest here....how mechanically inclined are you and how much do you know about the workings of the actuator and its parts?

[taroy1]

Yup, common interests and problems for sure. I'm definitely a shade tree mechanic. Software engineer by trade. I've taken a few auto mechanics courses through the county's adult continuing education program, enough to get past much of the intimidation of advanced projects. Since then, I put a reman steering rack on this truck, new leaf springs, and changed the timing belt. She's got 228k on the odometer and still runs sweet! Thus far, it sounds like we're on the same page with the workings of the actuator. More research pending.

[kennyyoung]

Sounds good to me ... I'm a backyard mechanic myself and pretty much do all my own work as well. I'm good to tackle most projects, but I am trying to take as much caution as possible before tearing into that actuator.... its a very expensive part. My next move is post#12 in this thread. I want to take the plate off the actuator, remove the actuator motor and try to turn the cog/shaft and try to get it freed up. My concern right now is taking off the motor and whats inside and under it.

[kennyyoung]

Hey man, I'm done for tonight. Keep in touch and I'll do the same. I'll be back on in about 8 hours!!!

[taroy1]

I took a good book to bed last night for my nighttime reading (factory service manual)
Since I can hear movement in my transfer case actuator, I know that it is at least partially alive. I believe that I am going to do some other testing before tearing into it. My truck has the vacuum powered A.D.D. (Automatic Disconnecting Differential) with its own actualtor on the front differential. There may be something in that system that is malfunctioning and keeping it from going into 4WD like the A.D.D. switch, one of the two solenoids, a vacuum leak, or the A.D.D. actuator itself. My first test will be to jumper the switch on the transfer case actuator and see if that is at fault.

[kennyyoung]

Yeah good reading...lol!!! I assume my truck has the vacuum powered A.D.D. as well, but I havent had the chance to check. That actuator is located on the passenger side up on the front differential isnt it? I'm starting to think that may be a problem for me to... or a problem that I may have caused earlier the summer. I replaced the transmission cooling lines running from the rad to the transmission a few months ago. It was a bit of an awkward job to do because of the limited space in that area and all the corroded brake lines, rack and pinion lines, and what ever else is down there (really hard to work around). Maybe I struck a vacuum line, electrical connection or something that got dislodged!!! Like I said, I'm finding it hard to get the time to actually do the work on the truck.... hoping to have a good day on Saturday to get this behind me!!! So, your going after pins 2 and 3 on the transfer case actuator (the grey connector pictured in the right picture in post #9 in this thread are you?

[taroy1]

Nope, I'm after the position sensor switch in the left photo. Theory is that if the switch is bad, the transfer case actuator might be working fine but the switch is not detecting it and fails to signal the ECU. That would likely cause the dash light not to come on and the A.D.D. system not to engage. Heh, it almost sounds like I have a clue with what I'm talking about.

[kennyyoung]

Ok, you can remove the position sensor switch and there is suppose to be a ball bearing at the end that can be checked and freed up if its sticking. I thought that it was basically only to activate the dash light to let you know when it was engaged.... so what you are saying is that it can cause the A.D.D. system not to engage? If that was the case..... I wouldnt have gotten the actuator to engage at all would I or we wouldnt be getting the clicking from the actuator would we? I know very little about the A.D.D. system!!!

[kennyyoung]

Ok, I'm back!!! lol

[taroy1]

I have not jumped into the wiring diagram so I don't know exactly what the interaction is between the actuator, switch, and A.D.D. system. But, a methodical diagnostic approach starting with the easy stuff is how I plan to attack it.