Rear locker stuck help

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C

CowThief

Joined
Dec 5, 2025
Threads
4
Messages
26
Location
Union, KY
Hey everyone, looked at a few threads on this issue and I'm gathering opinions on how I should proceed next.

The other night I had just finished up replacing transmission hoses, took it out for a spin and tested all the features of my triple locked 97 fzj80 checking to see if everything was "road-trip ready" or at least close. Want to hit some trails and don't want anything to surprise me if it doesn't work. Anyway, part of that is testing things such as the low range and all three lockers.

I tried everything three separate times (had to get transmission fluid level right so I took it for a couple laps). Will say the front has never worked, although not high on my list of priorities. On my first attempt the center lock worked flawlessly as well as the rear, I was actually surprised at how quickly it engaged. Second try only the center lock came on. And finally on the third attempt the center worked well and so did the rear... except that when it was time to head back the rear would not disengage. Rolled back and forth, changed it from low to high back to low several times. Nothing worked. I knew it was locked as I could hear the tires slip and feel the rear not want to turn. Ever so carefully got myself and the cruiser home, avoiding any sharp turns and called it a night.

Fast forward to today, I built a makeshift "obstacle". This being a bunch of mulch stacked on top of each other in an attempt to create a situation that would possibly challenge the rear axle, or at least simulate some slippage. Rolled back and forth on this contraption for a solid 20 minutes, using both low range with the center diff lock on as well as just having it in 4H. Nothing changed about my situation, did a few gradual S shaped turns in order to confirm and yep, still binding and skidding. Considering going to my gf's place, she has a field I could try to do some figure 8's in, just worried about damaging the rear as it's a little less than twenty minutes of driving which has some normal turns.

Now I've got the rear jacked up in the garage in an attempt to turn the wheels and see if it'll come loose... and then I realized all four tires need to be jacked up to try and dislodge the rears from each other :doh:. I'm new and have a limited tool set. Considering running down to a harbor freight and grabbing two more jack stands.

Have tried to do my research on this topic, looked at:

uscmas412

Thread 'Rear Diff Locked and Won't Disengage'

First off, this isn't my Land Cruiser. It belongs to @SmokeSkiCA . It's been sitting in my driveway for three years after he got orders to Japan. It had a fair amount of rust damage when he bought it, so we started ripping it apart and treating the rust. Both front and rear axles were rebuilt in this process.

I FINALLY got brakes lines installed in order to safely move it around the driveway but I don't have a locked version so I'm unfamiliar with how this should work.

SYMPTOMS: Audible clunk and corresponding thud from the rear of the vehicle (rear axle I believe). The...

CPACruiser

Thread 'Factory Rear e-locker wont disengage'

I did a search and found plenty of "locker won't engage," but unfortunately that not my issue, but maybe it's a similar diagnosis?

I was out snow wheeling last night and had the rear locked a few times and it worked flawlessly....until it was time to go home and it wouldn't disengage. I tried figure 8s, I tried reverse...i tried removing fuses, i tried negative battery terminal removal...

Even when selecting 4hi it doesn't turn off!!😡

I'm assuming I need to pull the actuator and possibly see if it's all gunked up inside on the gear/pins? Manually push the locking mechanism to off? Then...

clownmidget

Thread 'rear e-locker actuator rebuild pics'

Finally got around to doing this after putting it off for near two years. Like many, I had experienced the "sticky" actuator, tried "exercising" them, got it to work most times, sometimes just lived without it, etc. Last month it actually got stuck in the locked position with about 200 highway miles between me and home. The trick that time was to actually just let the truck cool down for four hours and everything moved just enough to let me unlock it.

I've rebuilt the front and I will say IMO, it is harder than the rear. For those that have considered it, I say go to it, it's not...
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The overall consensus I'm gathering is that the actuator is going to have to be opened up and the actual locker is going to need pushing out of position. One note I have is that I can hear clicking whenever I turn the locker dial.
Godwin said:
Assuming the rear locker is locked you can manually unlock it. Pull the locker actuator motor cover, pull the indicator switch and you'll have access to the actuator shift rod and shift collar. Remove the bolt that connects the shift collar to the shift rod and you can manually unlock the diff. You'll likely have to jack up one tire to rotate an axle shaft and more easily unlock the rear.
Click to expand...

Or @CPACruiser describes an alternative method.
CPACruiser said:
I couldn't pull the gear faceplate off, the first two 10mm broke off even with heat...so I took off the sensor plate and removed the 10mm bolt in the fork, pushed the fork towards the PS and it released the locker!
Click to expand...
Couldn't really visualize or decipher what they meant by this

My issue is I'm not too sure how able I'll be to get any of these aforementioned pieces or bolts off. Apprehensive because my lc isn't the cleanest on the underneath (or anywhere, for that matter). So far I've doused everything in some penetrating fluid, letting that sit and work. Would have to buy some way to heat as well or an extractor set and @CPACruiser mentions that
CPACruiser said:
the one bolt is in a precarious spot on top of the axle and I rounded the head on it...tough spot to heat also bc of the electrical for the locker.
Click to expand...
Making me wary of using heat.

So I'm asking for any help or advice on how I should proceed next.
Risk damage and go do some figure 8's?
Go grab jack stands and try to rotate the tires?
Risk snapping the bolts to the actuator cover? (or could someone explain or photograph where the sensor plate would be).
I'm also aware that the differential oil likely needs to be changed, do I just swap it out and try wiggle the car around again? Worried about this approach as well since the fill bolt looks pretty rounded.

I know I sound like a basket case rambling about the context of the situation and my nervousness of attempting the previous fix but I need this car back on the road soon and can't afford breaking something major/difficult to undo. I'm okay with just disconnecting something and not touching the rear as long as the wheels turn without risk of damaging the diff. Will attach pictures of what actuator is looking like so that someone can either point out the sensor plate or tell me if I'm overreacting about the condition of my undercarriage. What should be on my list? More jack stands? Differential Oil? Bolt extractor set?

IMG_6344.webp

Actuator cover

IMG_6346.webp

Is this the sensor that was being referred to? Just try and get that out with a spanner?

IMG_6347.webp

IMG_6348.webp

The refill and drain bolts I'm worried about.

Thank you and sorry for such a long and incoherent post
 
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Dude, calm down.
First undercarriage does not look that bad as far as rust goes, yes use penetrating oil but use the proper tools and techniques. Before you start unbolting stuff do more diagnostics and keep the scope limited. I.e. There is no need to mess with drain and fill plugs to diagnose thge lockers.

First chock your wheels for safety. Shift the transfer case to neutral. This will divorce the front axle from the rear. Jack up the rear axle. With both wheels off the ground the wheels can be be rotated. If the axle is locked both wheels will turn in the same direction. Unlocked they will rotate in opposite direction. Use the movement while rotating, with the key "on" to see if it unlocks.

A frequent cause of factory rear locker not not disengaging is that axle splines where the locker collar travels gets twisted. Search the forum for more info.
 
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Sorry, it's just a bad time to have my primary vehicle out of service. But that's what I get for getting an almost 30 year old truck and expecting nothing but sunshine and rainbows lol. Lesson learned. Anyway, was able to source some extra stands from a friend, got all four wheels off the ground. Did what you guys said, trans and T-case in neutral turning the back passenger wheel. Still no luck.

Looked into the axle shaft removal and inspection. Doesn't seem too complicated. Am I seeing right that it can be done without the removal of the tire? Or am I too naive. Looking at 1997 FSM SA-63 through SA-65 and it seems that way? If that does turn out to be the culprit I should expect to buy a new axle shaft along with the along with the other non-reusable items correct?

Also, @NeverFinis, thank you for the clarification, I understand what I'm looking at now.

So I guess it comes down to which one should I try first? Inspect axle shaft or try to manually unlock the locker.

Thanks for the help
 
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No, as in both rear wheels turned simultaneously when turned both clockwise and counterclockwise. Also, when spinning rear wheels the front ones did as well despite the t-case being in neutral, assumed it was fine. The front ones spin independently and opposite of each other when they are pushed, no activation from rear wheels. E-brake was not on.

All the wheels are spinning just trying to get the back ones from being locked, sorry for any confusion.
 
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CowThief said:
did a few gradual S shaped turns
Click to expand...

Do this, but while coasting with the transmission in neutral.

For these lockers to unlock, you need to take any tension/load off the driveline.
In a manual, slipping into neutral, or just popping the clutch in is often enough to release the tension/ load on driveshafts, diff etc

CowThief said:
So I'm asking for any help or advice on how I should proceed next.
Risk damage and go do some figure 8's?
Click to expand...

Unless you really beat on it, doing figure eights is not going to kill it. It's also not what you need to do to unlock them.
It's a guaranteed way to get them to lock.
 
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Interesting. I'm rather positive the shifter is in the correct place, between the farthest forward position and before the center diff lock and abs light turn on. I'll describe the movement of the wheels in each position.

H - When turning the front right passenger wheel by hand, the other front wheel turns the opposite direction as expected. When I initially start movement, the back wheels fidget a slight amount in the same direction as front wheels but don't move very far, stop their path after half a second. Noticeably more movement on the passenger rear than driver rear.
When turning the front driver wheel all wheels move similarly except I couldn't see any movement from the driver rear.
When turning either rear wheel all four wheels moved together.
N - When in neutral, or what I'm assuming is since it is the position right before the center diff lock and abs light turn on, the tires move the same as when in H. All four spin when rear are touched, the rears move slightly when the front are touched. And by slightly I don't mean slowly turning, I mean the wheel will turn for just a second and then stop - especially when changing direction of rotation.
L - The center lock and abs light turn on, needed to run the engine for the lights to actually activate though. The lights wouldn't when I went to shift it while the key was in the on position. Now activates each time shifting into L, or the lights do at least. Same behavior of the tires, only difference is when pushing the rears they are harder to rotate while still spinning the fronts. Very confused. Something I'm not doing right? Or could something be wrong with my transfer case? Will also say the rear locker light has been on during this whole process.
 
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mudgudgeon said:
Do this, but while coasting with the transmission in neutral.

For these lockers to unlock, you need to take any tension/load off the driveline.
In a manual, slipping into neutral, or just popping the clutch in is often enough to release the tension/ load on driveshafts, diff etc



Unless you really beat on it, doing figure eights is not going to kill it. It's also not what you need to do to unlock them.
It's a guaranteed way to get them to lock.
Click to expand...
Okay, is it alright to do this on pavement? It's what I've got access to atm.
 
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mudgudgeon said:
Either that or seized VC in the tcase.

If the VC is seized, it will be hard to get the driveline to unload
Click to expand...
Ah so I suppose I'll try the S's out and report back? I will also say that I have an extra hazard button next to my rear heater switch. Looked it up a little while ago and found that it may be a cdl button. Was on the dash when I got it, messing with it doesn't seem to do anything.
 
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mudgudgeon said:
Do you hear the centre diff lock actuator whirring when you shift between LO & HI?
Click to expand...
Well I did previously. Went to test it and now heard nothing. Started the engine up. Heard some unpleasant sounds between low and high but no lights. I have had transmission shifter in neutral. Tried shifting transmission around seeing if that would free things up while in low on the transfer case. CDL light and ABS light came on when put into reverse? Put trans back into neutral. Turned engine off. Now it's working again with the key in the on position. Hearing whirring as well as the lights popping up. Real confused on this. All four wheels still acting the same moving when touched but harder to move all four with the rears when center is locked.

So, correct me if I'm wrong, the cdl is always slightly activated? But more activated when put into L on the transfer case, although sometimes the cdl lights won't turn on when transmission and transfer case are left sitting. Hoping I'm gathering that right
 
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CowThief said:
correct me if I'm wrong, the cdl is always slightly activated?
Click to expand...

No. It's either engaged or disengaged, or broken.

All the lockers in your cruiser use very coarse gears to lock shafts together.
The rear diff locking gear has 6 teeth. (front & CDL are similar)
The gears have to line up almost perfectly for the locker to engage. If you are sitting stationary, chances of these chunky teeth being lined up just right in any of the lockers is slim.
This is why figure 8s or S turns are suggested. This makes your wheels turn at different speeds, which rotates the diff gears. Eventually the teeth will line up
 
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mudgudgeon said:
No. It's either engaged or disengaged, or broken.

All the lockers in your cruiser use very coarse gears to lock shafts together.
The rear diff locking gear has 6 teeth. (front & CDL are similar)
The gears have to line up almost perfectly for the locker to engage. If you are sitting stationary, chances of these chunky teeth being lined up just right in any of the lockers is slim.
This is why figure 8s or S turns are suggested. This makes your wheels turn at different speeds, which rotates the diff gears. Eventually the teeth will line up
Click to expand...
Okay, so it's likely the different gear ratio which is making the wheels harder to turn at L when it shows the cdl locked, even though it's constantly locked. Learning a lot ty.

So looks like I've got a VC to take out from what I've skimmed. Will read further

Looks like a good tutorial
MikePL

Thread 'Tutorial: removing the viscous coupler (photos)'

What pushed me to do the viscous coupler removal?

First of all when I made turns, for example, in a parking lot, I heard my tires scrub against concrete and one of the wheel stopped turning intermittently to relieve the stress on the drivetrain. Please note that my tires weren't squeaking but really dragging to the point that the truck would not roll while making a turn. Instead, it behaved as if the parking brake were applied. If your tires just squeal, especially on the slick kind of concrete found in shopping malls, then the VC (viscous coupler) is not your problem. Another way to find...
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I hate to sound like such a cheapskate but that looks like one decent project that I'll need to buy stuff for. Namely good wrenches as I've just been using harbor freight. Would it be wiser to manually unlock the rear diff following these instructions

CPACruiser

Thread 'Factory Rear e-locker wont disengage'

I did a search and found plenty of "locker won't engage," but unfortunately that not my issue, but maybe it's a similar diagnosis?

I was out snow wheeling last night and had the rear locked a few times and it worked flawlessly....until it was time to go home and it wouldn't disengage. I tried figure 8s, I tried reverse...i tried removing fuses, i tried negative battery terminal removal...

Even when selecting 4hi it doesn't turn off!!😡

I'm assuming I need to pull the actuator and possibly see if it's all gunked up inside on the gear/pins? Manually push the locking mechanism to off? Then...

and having at least something drivable? It had been driving rather fine as it was before the rear locked up. Or would it not be worth the risk.
MikePL said:
This puts enormous stress on your axles, driveshafts and all differentials.
Click to expand...

My main priorities atm are:
Unlock rear diff, manually if I have to.
Front Knuckle rebuild - click click click
VC removal
along with a laundry list of little things but those seem to be the most dangerous to ignore.

What would you suggest? Is the VC wearing out really going to have me buying a differential soon? Or can I unlock the rear manually and at least have something to drive back and forth between school, work, etc. Wouldn't really plan on wheeling and road trips until I get some of this stuff sorted out.
 
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VC frozen on my 80 when I got it, first thing I did, IIRC maybe a couple of hours and it was my first time in. I didn’t replace it, easier to add a CDL switch for when you might need 4WD like snow or ice. Good luck!
 
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