Factory Rubicon rear locker stuck closed

Jalax23

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Original poster
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Mar 28, 2021
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Topsfield ma
So I swapped out the rear end in my jeep. The old was was completed rusted out and seals were gone. I put an 03 rublicon Dana 44 in my 98 tj. From what I understand the rublicon rear end is an air locker. I don’t have a lift and do not take the jeep off road. It is going to be for the family to go back and forth to the beach all paved roads. I thought that I could simply not hook up the locker. When I put everything together I took for a test drive and found the rear locker is locked. Not sure the best way to figure out why or how to unlock it. Any help would be greatly appreciated.
 
When I put everything together I took for a test drive and found the rear locker is locked.
The rear has a type of limited slip that may appear to seem locked when on a dirt road and you “peel out”. Otherwise you can jack it up and see if when you spin one tire the other should rotate the opposite. Unless it really is all messed up, then you need to open it up and find out what may be the problem.
 
So I swapped out the rear end in my jeep. The old was was completed rusted out and seals were gone. I put an 03 rublicon Dana 44 in my 98 tj. From what I understand the rublicon rear end is an air locker. I don’t have a lift and do not take the jeep off road. It is going to be for the family to go back and forth to the beach all paved roads. I thought that I could simply not hook up the locker. When I put everything together I took for a test drive and found the rear locker is locked. Not sure the best way to figure out why or how to unlock it. Any help would be greatly appreciated.
Pull the fill plug and check it again.
 
The fill plug can be set in too far causing it to hit the locker. Like said above, either pull it or back it out a few turns and test it by jacking up both wheels and spinning them by hand..
 
Is the Solenoid that releases the air in the locker inside the pumpkin? Is there a chance the bladder still has air in it with out the compressor hooked up? Going to check the fill screw when I get home just seems to easy.
 
Is the Solenoid that releases the air in the locker inside the pumpkin? Is there a chance the bladder still has air in it with out the compressor hooked up? Going to check the fill screw when I get home just seems to easy.
With no pump the line would be open so no air in the bladder.
 
Pull the fill plug and check it again.
Bingo, the locker flange is 100 percent visible, it’s also likely it was messed with and the sensors mushroom head is behind the flange holding it cocked , it’s on the upper front side of the diff and not visible from the fill plug.

it can be removed by carefully unscrewing it and replaced with an oil fill plug the same thread size .

Don’t force it , and if it breaks off pull the cover and get it out, but it shouldn’t.

Unless there is air to the line and it’s a pinched I don’t know of a reason why that locker would be engaged....they are disengaged at rest.

You might take a flat head screwdriver and prior to the right only flange Through the fill plug And see if it pops over.

Also you need to verify that you have the same gear ratio front and back and if you don’t do not put the vehicle in four-wheel-drive at any speed.
 
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Is the Solenoid that releases the air in the locker inside the pumpkin? Is there a chance the bladder still has air in it with out the compressor hooked up? Going to check the fill screw when I get home just seems to easy.
No. There is practically no chance if the line is disconnected that it is holding air
 
With no pump the line would be open so no air in the bladder.
Bingo, the locker flange is 100 percent visible, it’s also likely it was messed with and the sensors mushroom head is behind the flange holding it cocked , it’s on the upper front side of the diff and not visible from the fill plug.

it can be removed by carefully unscrewing it and replaced with an oil fill plug the same thread size .

Don’t force it , and if it breaks off pull the cover and get it out, but it shouldn’t.

Unless there is air to the line and it’s a pinched I don’t know of a reason why that locker would be engaged....they are disengaged at rest.

You might take a flat head screwdriver and prior to the right only flange Through the fill plug And see if it pops over.

Also you need to verify that you have the same gear ratio front and back and if you don’t do not put the vehicle in four-wheel-drive at any speed.
Ok so today’s update... pulling the fill plug out did not solve the issue. I took the cover off and drained the rear end. If I spin the tire there is some play and the disc for the locker seems to be disengaged. When the gear line up you can see the disc for the locker move towards the driver side and engage the locker. When you let go of the tire and let tension off the disc moves back again. I am lost. Next is to take out the rear dif and take a look at all the parts. The gear oil was milky so I am worried that the bladder may have water in it also since the air connection was open the entire time when the rear end was sitting for who knows how long.
 
excuse my ignorance here. But, how about wiring up the locker and use it when/if needed?
 
I’d pull the cover and spin the axles til the locker disengages, they like the vehicle to be turned to disengage really .

the fill plug likely had it bound in a locked or partially locked situation and it hasn’t unlocked fully. If there are scars on the inside of diff plug from the flange that tells the story likely.
 
I’d pull the cover and spin the axles til the locker disengages, they like the vehicle to be turned to disengage really .

the fill plug likely had it bound in a locked or partially locked situation and it hasn’t unlocked fully. If there are scars on the inside of diff plug from the flange that tells the story likely.
Did that and it will not release it looks like there is a disc on the right side with tongs that stick out. On the left side are larger thicker pieces that stick out and the locker engages when these two sets intertwine. Do both retract when the locker in open?

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That locker is cocked on the sensor pin in back it appears , remove the sensor pin and find the correct oil drain plug at a parts store.
 
You can also see it behind it with a small inspection mirror I think . Behind the locker , about 10 o clock if you faced it
 
How do I remove the sensor pin? Do I have to take the rear differential out?
No ...It is in my earlier post.

It’s screws into the front of the differential on the passenger side at the top comes in over that flange. You will see where it has a nut and plug in sort of like an oxygen sensor.
 
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