Center Diff Lock - Won't Engage

On a different note I think the reason I got mud and stuff in the actuator, is theirs a breather hose up on top of the actuator and wasn't on there very well.
 
BlackWorksInc said:
Actually, yes it does. Some good hard taps on the case near the actuator tend to help in most cases.
Click to expand...

Ok, I should probably ask these questions in one big pile rather than keep asking you one per day.

When to I bang on it? Should I have my wife push the button and tap it as she does that? Should it be in neutral or park or drive?

I usually make everything complicated, so I apologize, just want to make sure I do it right.
 
Try a least invasive approach first: loosen the bolts 1 turn and tap the box, then try the switch for center lock. If no go, do again but somewhat harder taps/hits.

Next, losen bolts 1 more turn, no more. Tap again, try the switch. If no go, turn the switch and tap at the same time the motor is trying to engage center lock.

Most posters seem to report results after trying 5-10 attempts with tapping and engaging. Don't give up after 3, etc

Also, check that small breather line on the very top of the actuator box, it's a straight nipple, no barb or flare and no clamp so they come off on their own once the rubber decays.
 
Is there a particular gear oil that can be added to help break the gears free inside the transfer case? Is it due to the actuator being stuck or the gears in the transfer case the actuator is engaging being stuck? Just wondering. Could adding synthetic fluid or even some sort of high cleaning agent transmission fluid additive to the gear oil work to clean up the inside of the TC? I will be checking my breather line this weekend to make sure its still there. Never knew it had one.
 
The transfer case takes gear oil, u would not use anything else.

Most of the engagement issues are actuator related it seems, not the case internals jamming. Though, if you never used 4Hi for 5 years, the center diff may be stuck too.
 
Greydog said:
Try a least invasive approach first: loosen the bolts 1 turn and tap the box, then try the switch for center lock. If no go, do again but somewhat harder taps/hits.

Next, losen bolts 1 more turn, no more. Tap again, try the switch. If no go, turn the switch and tap at the same time the motor is trying to engage center lock.

Most posters seem to report results after trying 5-10 attempts with tapping and engaging. Don't give up after 3, etc

Also, check that small breather line on the very top of the actuator box, it's a straight nipple, no barb or flare and no clamp so they come off on their own once the rubber decays.
Click to expand...


Thanks for the detailed write up.

Fwiw, I can get it to go into 4lo, It's the center diff lock that's not working.
 
Right, I may be wrong but I thought one of the shift shafts the actuator moves is to engage center diff lock?
 
ben550 said:
Is there a particular gear oil that can be added to help break the gears free inside the transfer case? Is it due to the actuator being stuck or the gears in the transfer case the actuator is engaging being stuck? Just wondering. Could adding synthetic fluid or even some sort of high cleaning agent transmission fluid additive to the gear oil work to clean up the inside of the TC? I will be checking my breather line this weekend to make sure its still there. Never knew it had one.
Click to expand...

Greydog said:
The transfer case takes gear oil, u would not use anything else.

Most of the engagement issues are actuator related it seems, not the case internals jamming. Though, if you never used 4Hi for 5 years, the center diff may be stuck too.
Click to expand...

Greydog said:
Right, I may be wrong but I thought one of the shift shafts the actuator moves is to engage center diff lock?
Click to expand...

The issue from what I have seen from the one and only one I got to tear apart was that some sort of crusty/rusty/gunky crap forms in between the plastic gear and shaft that actuates the CDL and/or 4WD from lack of use and age (not sure what kind of grease they use, but it looks like it might have been a white lithium based one?) That gunk becomes pretty hard/sticky and is enough to keep the gear from turning, the big issue is that the there isn't a whole lot you can do besides tapping/wiggling the actuator because no one as far I know has been able to successfully time the actuator after taking it apart.

That being said it probably wouldn't hurt to get some good lube in the transfercase in case the shift rods/sleeves get a little gunky as well, but that usually isn't the case.
 
BlackWorksInc said:
The issue from what I have seen from the one and only one I got to tear apart was that some sort of crusty/rusty/gunky crap forms in between the plastic gear and shaft that actuates the CDL and/or 4WD from lack of use and age (not sure what kind of grease they use, but it looks like it might have been a white lithium based one?) That gunk becomes pretty hard/sticky and is enough to keep the gear from turning, the big issue is that the there isn't a whole lot you can do besides tapping/wiggling the actuator because no one as far I know has been able to successfully time the actuator after taking it apart.

That being said it probably wouldn't hurt to get some good lube in the transfercase in case the shift rods/sleeves get a little gunky as well, but that usually isn't the case.
Click to expand...

I stuck my head under my truck this morning, it look like the vent hose is in there. I wasn't able to check it for any splits though cause I was in my work clothes etc.

I had a thought. Is there anything appropriate I could spray into the housing via the breather hose that might help loosen it up? This might be extreme, but if I could find a electrical friendly cleaner, I could drill a 1/8" hole in the bottom corner of the housing, let it drain out, spray some lube in there and then epoxy the hole?

Maybe thats all crazy talk. Just trying to be creative.

I'm gonna start banging on it today.
My plan is to bang on it with a dead blow 10 or 15 times while my wife tries to engage the CDL.
If that doesn't work, go to the 'invasive method' as mentioned earlier, i.e. loosening the bolts a little and tapping it.

I'm supposed to attend the Toyota Jamboree this weekend, so not having CDL is gonna suck.
 
Last edited:
Ok... Update.
I did all the above, and while doing so, I realized that there is NO breather hose on this unit.
(Correct?)

So can I try to flush it out? I can't remember who all has opened one of these up, or who had the pic of the gears mucked
Up with mud.

If you will recall, I swamped my truck pretty bad about 5-6 weeks ago and it hasn't worked right since.

Any help is appreciated. I'm supposed to go to the Toyota jamboree this weekend so fixing this would be nice.
 

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swapmeet said:
So, I guess I'm gonna have to get this fixed professionally?

No way to replace the actuator diy correct?
Click to expand...

If you have a place to drop the transfer case, then you can do it at home a member made a great write-up on how to replace the actuator a few months back. The link should be in the Toolbox sticky. :)
 
Greydog said:
Try a least invasive approach first: loosen the bolts 1 turn and tap the box, then try the switch for center lock. If no go, do again but somewhat harder taps/hits.

Next, losen bolts 1 more turn, no more. Tap again, try the switch. If no go, turn the switch and tap at the same time the motor is trying to engage center lock.

Most posters seem to report results after trying 5-10 attempts with tapping and engaging. Don't give up after 3, etc

Also, check that small breather line on the very top of the actuator box, it's a straight nipple, no barb or flare and no clamp so they come off on their own once the rubber decays.
Click to expand...

I'm going to try this soon. My center diff light just flashes and won't engage.
 
Tried banging on the unit with a rubber mallet while engaging at least 5 or so times. No luck. Found that my breather line was decayed and had fallen off. Trimmed it and reattached it.

Going to try more of the banging on the unit and engaging with the wife's help. Then I'll move to the loosening of the bolts, banging, and engaging. I can hear something inside of it working, and that beeping, so I'm hoping it's not completely broken.
 
I too have a case of the stuck center diff. Would I be doing any damage if I engaged the switch on my morning drive to work and let it try to engage for awhile each day? I figure maybe the potholes and railroads I drive over my shake it loose but I don't want to be doing something that will damage the system by leaving it try to engage for 15 or so minutes each morning.
 
After reading the thread I went and ran through everything. 4H/4L engaged and disengaged. When I first started it took awhile to even get 4H to engage when already moving as well as Center Diff Lock. After about 15 minutes of going through everything, driving across the yard it operated much quicker and smoother. There is an audible clunk as Center Diff Lock engages. Is this normal?
 
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