Help with diagnosing issues on my 2005 LJ Rubicon lockers

RustyAutoholicGuy

RustyAutoholicGuy

Diesel Wrangler Guy
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Hey TJers/LJers,

First off I'm about to run out for a date with my wife which I'm already an hour late for so I will be responding this evening but wanted to go ahead and post this!

My lockers are not engaging on my LJ Rubicon, I press the Axle Lock button down twice and I just have the two flashing lights on my dash. I have done the following:

  • Verified both pumps are turning on
  • Replaced both front and rear lines (dry rotted)
  • Verified I can clamp off the ends of the new hose and both pumps stop
  • Removed front diff cover and checked the line
At this point I want to also say I can BARELY feel air coming through the line inside front diff. If I clamp off the hose inside the front diff the pump never turns off, and it feels like a significant amount less psi coming through the line.

I haven't taken the rear Dana 44 apart yet though at this point I'm kind of assuming they both have the same issues and it was a good time to also replace the gear oil in my axles with GL-5 oil.

Is it possible that the hard line going into my Dana 44 is clogged and can I blow the hard line out with an air compressor?

Thanks
Grant
 
RustyAutoholicGuy said:
Hey TJers/LJers,

First off I'm about to run out for a date with my wife which I'm already an hour late for so I will be responding this evening but wanted to go ahead and post this!

My lockers are not engaging on my LJ Rubicon, I press the Axle Lock button down twice and I just have the two flashing lights on my dash. I have done the following:

  • Verified both pumps are turning on
  • Replaced both front and rear lines (dry rotted)
  • Verified I can clamp off the ends of the new hose and both pumps stop
  • Removed front diff cover and checked the line
At this point I want to also say I can BARELY feel air coming through the line inside front diff. If I clamp off the hose inside the front diff the pump never turns off, and it feels like a significant amount less psi coming through the line.

I haven't taken the rear Dana 44 apart yet though at this point I'm kind of assuming they both have the same issues and it was a good time to also replace the gear oil in my axles with GL-5 oil.

Is it possible that the hard line going into my Dana 44 is clogged and can I blow the hard line out with an air compressor?

Thanks
Grant
Click to expand...

This one sounds a little silly, but it worked for me. To verify if the lockers themselves work, with the rear wheels off the ground, do the following:

- place the transmission in neutral
- remove the original rear or front air supply line from the housing
- attach a small piece of comparable new line to replace the one you removed (I used a 2' piece)
- blow into the hose you attached and spin the tires

Since the lockers only need 5 - 6 PSI, blowing into the hose will be enough to activate the lockers for testing purposes. I did this on a previous Jeep, when I had a similar problem. For me, it ended up being the original air supply line, which was bleeding off air at the housing air fittings. After I knew the pumps and lockers worked, I installed all new line and everything worked again.

This may not be your issue, but at least you'll know if your lockers work. Once you've done one, simply repeat for the other.
 
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The hose inside the diff tends to deteriorate over time and can be replaced with 3/16" fuel line. This could be the issue with the rear locker.

I believe there's a thread here somewhere that mentioned the steel hose connection on the diff rusting through. A blockage wouldn't cause the pumps to keep running, just the opposite. Sounds to me like you have a leak in/on both diffs.

If I understand what you describe correctly, there has to be a leak in the metal fittings on the diff, probably the outside fitting. A leak is the only thing that causes the pump to keep running assuming the pump works correctly. Yours seems to be working correctly, based on your description.
 
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You can also blow more psi as long as the lockers are installed, like 10-20 , from the pump forward and remove the fill plug ..you will know real fast if the fitting is clogged , failing , or if the line inside is rotted or off ...I was able to diagnose one like this recently. You will see oily vapor come out ...and you can observe the locker action to.
 
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If the pump isn't turning off when you plug at the diff does it stop if you plug it right at the pump?

The pumps can often leak internal so while they sound like they are on they really aren't pumping enough PSI out the hose to inflate the bladder. I have 4 pumps that do this.. I've now got a box of 7 pumps the 3 others will not even turn on.
 
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Thank you for all the responses! So I tried bypassing the fitting on the axle housing on my front axle and the locker immediately engage and showed as locked on my instrument cluster as well.

Also I can plug off the hose to the pumps and they'll turn off and stay off.

So I'm at the point where I need to figure out what's going on with the plumbing going through my axle housing.

Is there a check valve in there or is it a straight through piece of metal tubing?

Thanks
Grant
 
It's a straight fitting , and you can find threads where guys have modded those on the net .... pull the fill plug ...then put air to the line ....if it's leaking in the diff or plugged you will know immediately.

You can see it move the flange on the locker from the fill plug.

Normally it's the line degraded, not the fitting.
 
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AndyG said:
It's a straight fitting , and you can find threads where guys have modded those on the net .... pull the fill plug ...then put air to the line ....if it's leaking in the diff or plugged you will know immediately.

You can see it move the flange on the locker from the fill plug.

Normally it's the line degraded, not the fitting.
Click to expand...

I put a new piece of hose on the inside which didn't help so it has to be that fitting!
 
RustyAutoholicGuy said:
I put a new piece of hose on the inside which didn't help so it has to be that fitting!
Click to expand...
I researched the web a while back when I was chasing an air leak on my 06 rear and some guys have come up with good fixes.....be sure to post what you find and do for us Rubi guys.
 
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Well Houston I think we have a problem . . .

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As soon as some parts stores open this morning I guess I'm making a new one, at this point I think this is the issue with my rear locker as well.

-Grant
 
I am pretty sure I am in this same fitting situation based on some testing I did last night on the air supply to my rear locker.

@RustyAutoholicGuy Were you able to find the fittings at a reasonable price or did you end up with another solution?

All the prices I am seeing from searching the part number are $100+ as well. Insane.
 
That is ridiculous!!! For that 50 cent piece of crap they want $38 - $108?!!!!!! Would a brass bulk head fitting work?
 
FireJeep said:
That is ridiculous!!! For that 50 cent piece of crap they want $38 - $108?!!!!!! Would a brass bulk head fitting work?
Click to expand...

The prices I have seen range from $108-$167. I get that there are supply chain issues due to Covid and TJ parts are getting harder to find, but this is simply ridiculous..

See Google shopping results here.

I'm going to pull the fitting at some point today to check and see if it rusted out or damaged. Hopefully I can just crank up the PSI and blow some air through it to clean it out.
 
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