Rear locker woes. :(

[SoCalMonty]

Rear isn't locking up. Confirmed my suspicion today in the dirt. I was hoping it was just the rear detection switch, but it wasn't.

1) Connected hand pump's gauge to rear diff pump outlet (at the end of the hose that connects to the diff). Perfect 5psi.

2) Removed rear diff detection switch, checked with multimeter...checks out OK. (ps...why does it say I have to remove the differential to take this switch out? What does the end of the pin connect to? I was able to get it back in by rotating the rear tire a bit until it felt like it lined up and wasn't hitting anything...).

3) Applied 5psi via hand pump directly to rear diff inlet. Wheels feel like they "lock" more firmly together when the pressure is applied, but they still turn the *opposite* direction.

4) Lost 0.5psi in about 120 seconds of turning the wheels and watching the gauge...the needle moves slightly as I would turn the tire back and forth (lock to lock...it was in park), but it doesn't seem to be a leaker.

What the heck could be wrong?! I'm really perplexed. Anyone have any ideas?

 

[stioc]

Hmm, I don't know anything about the Mitsu diffs but you mentioned 5psi, is that what it's supposed to be per the FSM? I ask because my ARB requires about 80psi to engage the locker.

 

[IncorpoRatedX]

yes, mitsu lockers are low pressure.

 

[SoCalMonty]

yes, mitsu lockers are low pressure.

Yeah, same as Jeep Rubicons.

 

[IncorpoRatedX]

when the locker engages, the wheels will only spin in the same direction, never in opposing directions. Sounds like the locker is not locking.

 

[4D55 Performance]

Yeah, same as Jeep Rubicons.

The Jeep JK uses an Truetrac E-locker not a air locker. I believe the TJ Rubicons used an air locker.


As for your issues with the Monty, I am betting it is a stuck or faulty solenoid.

 

[SoCalMonty]

when the locker engages, the wheels will only spin in the same direction, never in opposing directions. Sounds like the locker is not locking.

lol...hence the whole reason for this thread!

It's getting air, and it's not leaking...so I'm trying to deduce, could it still be the actuator? Or is there anything else that could be bound up inside preventing it from locking up?

 

[SoCalMonty]

The Jeep JK uses an Truetrac E-locker not a air locker. I believe the TJ Rubicons used an air locker.


As for your issues with the Monty, I am betting it is a stuck or faulty solenoid.

Yeah, the TJ's. Forgot about the JK! Thanks!

I'm bypassing the 4WD computer and all switches...manually supplying air to the actuator in the rear diff, so it should be locking. It's a mechanical problem in the diff, but I would like to have an idea as to what it might be before I open it up.

Tomorrow I'm gonna pull the cover, pressurize it, and watch/listen to see if I notice anything. 9 times out of 10, it's an air supply problem, but unfortunately for me that's not the issue with mine!

 

[4D55 Performance]

The solenoid/actuator failure is very common on all vehicle that have a locker. If they are not used regularly they seize up from corrosion. Last month I took my Mercedes G500 to the dealer because the front locker was not working. They tried to get it to engage but it would not. So they removed, cleaned and inspected the solenoid on the bench, they said it was working properly. So they re-installed the solenoid and and now the locker works. They said they could not locate a problem now that the locker is working so I was not charged because the problem would not repeat itself again.

In reality I know what happened, they removed and cleaned the solenoid to see if it needed to be replaced but all it need was a good cleaning. The G500 uses a low pressure system just like Mitsubishi and it is so common for these things to freeze up. Give it a good cleaning and it should be good to go. If not just replace it, they are a pretty cheap part.

 

[SoCalMonty]

The solenoid/actuator failure is very common on all vehicle that have a locker. If they are not used regularly they seize up from corrosion. Last month I took my Mercedes G500 to the dealer because the front locker was not working. They tried to get it to engage but it would not. So they removed, cleaned and inspected the solenoid on the bench, they said it was working properly. So they re-installed the solenoid and and now the locker works. They said they could not locate a problem now that the locker is working so I was not charged because the problem would not repeat itself again.

In reality I know what happened, they removed and cleaned the solenoid to see if it needed to be replaced but all it need was a good cleaning. The G500 uses a low pressure system just like Mitsubishi and it is so common for these things to freeze up. Give it a good cleaning and it should be good to go. If not just replace it, they are a pretty cheap part.

Thanks for the tip!

It must have just been stuck, and I think I "unstuck" it accidentally while ruining something else. lol.

I removed the diff and bench tested it about 50 times, and it worked normally every single time. I bent the outer ring of the actuator slightly, from putting the detection switch back into the diff while it was in the car yesterday. Now I know why the manual says not to do that. haha. When the actuator moves to the "lock" position now, a section of the actuator ring contacts the tip of the pinion gear slightly. I bent it back into place as much as I could. It still rubs slightly when locked, but I figure it will be used infrequently enough, and at such low RPM's, it's nothing the neodymium magnets I have on the assembly can't handle.

The fat section of the switch's tip sits on the far side of the actuator, and there's not enough play in the switch to push it into the right place if the diff assembly is in the axle...the carrier MUST come out, the switch is then installed, and then the carrier goes back in so the tip of the switch is "stuck" on the far side of the actuator ring.

When it's unlocked and the actuator ring is toward the passenger side of the axle, the rod on the switch is pulled in by it's own spring, and there's no continuity in the switch - this causes the R/D Lock light to flash on the dash (not locked).

When you press the R/D Lock button, the actuator slides toward the driver's side to engage the teeth. When it moves, it also pulls the rod on the detection switch, tripping it and causing the light to go solid on the dash readout (locked).

I didn't have time to take everything apart again, reinstall, and reset everything. So I grabbed the Dremel and cut the rod off the switch, so it's basically just an "upper drain plug" now. lol. Didn't really have any other options, it was dusk at the time.

Everything is bolted up and it's on it's wheels again; the only thing I didn't have time to do was refill the diff! I'll do that tomorrow morning and then test her out.

If anyone here has wired the rear diff light so it comes on with the pump (or when the R/D Lock switch is switched to ON)...if you could tell me where to splice the wires and what colors they were, I'd appreciate it. I'll report back tomorrow on the diff situation...if it locks as normal finally, I'll try to record a little demo tomorrow.

 

[billygoats]

Any update on this Sean? I might be having the same problem with mine now. Pump and lines test ok. Locker won't engage. Flashing lights only.

 

[eurosonic]

I had an issue with mine as well. I changed the diff oil and it worked great ever since.

 

[billygoats]

Sadly the diff oil change didn't help for me. Gonna have to pull the 3rd next week and see what's going on inside. I'd like to do 4.90 since I'll have it out!

 

[jeep-N-montero]

My compressor is kicking on but just keeps running and locker doesn't seem to want to engage, if I plug the air line and the compressor turns off then shis should rule out a compressor issue, but where is the solenoid/actuator to clean and check?

 

[Eric M]

It goes into an actuator in the differential. Most likely culprit would be the air lines themselves, I think.