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Rubicon Lockers Not Engaging

8K views 23 replies 7 participants last post by  JackMacd 
#1 ·
I know there have been a lot of threads on this. I am hoping to get some advice from someone who has more knowledge than I do.

I have a 2005 Wrangler Rubicon Unlimited. Since I have had it the lockers have never locked. The lights have always blinked. Today I did more investigating. Both air compressors are working and I have air to the differentials. When I push the locker button the rear light blinks and it doesn’t lock. If I push it a second time the front locker locks but the lights (both) keeps blinking.

I have read that if the rear locker doesn’t lock the front will not lock. Anyone has experience with this?
 
#2 ·
Nope. The front should lock even if the rear does not.

Are you positive the both pumps work? Sometimes it may feel like they are pumping air but are not able to provide the full pressure to actuate the locker.

Can you physical talk by driving if the lockers are engaged?

If the pumps are working and pushing air the axles than the lockers would lock even if the lights didn’t work. You should be able to tell in 4 low on a dirt road when the lockers are engage. If they are engaged and the lights keep blinking than you probably just have an issue with the sensor in side the axle. ( it’s just a plunger that’s pushed when the locker engages.)

The only other possible issue is that the bladder in the differential it self is bad on both axles. I kind of doubt this but hey it could happen I guess.



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#3 ·
I am not sure how to check if there is sufficient air pressure. I know both front and rear are getting air.

I put the Jeep on 4 jack stands. The front locker locked and the rear didn’t. Both lights were blinking. I think the bladder in the rear is bad so the rear is not engaging. I think the front is engaged but because the rear is not engaged the lights blink.

Anyone have experience?
 
#4 ·
Could be the rear sensor, as EmbarkWithMark mentions. Replacing that is a little more involved. Check connections. Clean the terminals and the socket. Try that first and see what happens.

If no luck after cleaning contacts on the sensor... Could be simply gummed up from lack of use.

I would pop the cover, drain the rear diff fluid, clean it all out real good with cleaner spray and inspect.

Maybe a good cleaning is all that is needed to free up sticky parts. Cheap enough to do this and would not hurt anything.

I have an 05 Rubi. When I first got it, the lockers were not working. After a couple of tries, they finally "woke up". I think they had never even been activated and were just kind of stuck. Now I got them all working, I exercise them every so often on a gravel parking lot if I can't get to a trail (which due to work schedule is hardly at all, but I have to continue to be gainfully employed until I am old enough to retire...). With regular exercise, they seem to be working perfectly. Indicators and all.
 
#5 ·
With stock wiring they can only be locked in 4low at low speed and the linear pot the rubi case uses to sense transfer case position can be pretty problematic much more so then the simple switch used in the 231 case used in all other TJ


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#7 ·
Thank you for the input. I did do the S turn and still got the blinking llight.

I put the Jeep back on 4 jack stands and I hooked the rear hose on the front compressor. The rear didn’t lock. I then put the front hose on the rear compressor and the front locked.

This eliminates the air compressor issue. I think it is the locker itself. Has anyone replaced the locker? I see them for sale for about $150.
 
#12 ·
Do some simple trouble shooting. From the pump, disconnect the airlines going to the rears. Starting with the front, jack it up, put it in 4 low (assuming it's stock). Turn on the key (shouldn't need to be running, just in the "On" position), then have someone blow into the front line while you spin the tire. If it locks up, you know the problem is either the pump or something electrical. If it doesn't, then the problem is somewhere in the differential. These pumps only require 5 PSI, so this works and is the safest way to make sure you don't blow the bladder. Once you do the front, repeat for the rear.


Note: Don't be afraid to blow into the line hard to make this test work. You're not going to break the bladder by blowing into it.
 
#13 ·
I am going to open up the diff this week and take a look. I don’t have the money to put on ARB or another after market locker system so if I do need to replace the stock locker is this it?

https://www.quadratec.com/p/crown-a...MIp-7ei7-L5AIVDcJkCh22HwkUEAQYASABEgJJJfD_BwE

I am not familiar with what it looks like. I also read that if the drain plug is screwed on too tight it can cause the locker to not engage? Anyone has experience with that? I am going to try it this week.
 
#17 · (Edited)
If that part is actually bad, you can get it from www.rockauto.com for $80 where I have purchased two of them . Quadratec pricing is usually way too high. Look for Dana 84307 or the longer Spicer p/n shown in my screenshot.

Be advised it is very (!) tricky getting the carrier reinstalled which requires a special technique to avoid jamming the locker sensor hidden behind the carrier. If you get that far contact me and I'll give you some help on it. Only techs who have worked on Rubicon lockers know how to do it.
 

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#20 ·
Alright I jacked up one side of the jeep. I pulled off the rear diff cover and this is what I found. The air bladder/Actuator is activating but the locker is still not locking.

See link for videos.

https://www.dropbox.com/sh/j2ij0mqb0tk61lg/AAAlgf46o-XwXp1veThw0wxEa?dl=0

My two guesses are 1) air badder is not filling up all the way and not engaging the locker or 2) something is wrong with the actual locker.

I don't think it is the pump because I switched the front to the back and still had the same issues. The front diff locks with either pump.

I thought the air hose inside the diff might be cracked that is why there is a long temp hose in the video.

I might pull the front diff cover off just to compare.

Let me know what you think.
Thank you,
 
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