2006 LR3 Rear Locking Diff 'Pop' sound Diengaging

[Brent Keller]

Search and found a 2006 LR3 90k miles with rear locking diff.... That rear locking diff is not easy to find but I wanted it. First thing was had all fluids changed including front and rear diff + tranfer, trans, and oil. My thought was to drive over semi mild hills rutted sand on my property a couple times a week to engage the lockers in hopes this will keep the in better working condition vs lack of use.... And a bit fun.

Initially found rear diff rarely locked in Sand and Mud Rut but sometimes in Rock Craw even when needed. Now, rear diff engages more often and sooner in all three modes mentioned. However, if front and rear is locked and the LR3 climbing sand hill looses traction, I reverse to descend hill a bit and the rear diff unlocks. When the rear diff unlocks, it make a Pop or Clunk sound due to pressure on it when it disengages. That can't be good!
Questions:
1. Is this 'Cluck' normal? Is the a way to change gears or settings while driving to prevent the 'Cluck'
2. why does the rear diff unlock when put in reverse? I don't think the rear diff has ever locked in reverse. Is that normal? I wish the rear diff would just stay locked as it would help if your in a bad spot plus get you in a location where it would be free of stress and then no 'Pop' sound. BTW, when rear diff is unlocked when not in load, there is no 'Pop' sound.
3. is engaging the locking diffs weekly good?

Need your words of wisdom. I love this LR3 and want to keep it a long time.

 

[Houm_WA]

When you are in reverse, your rear locker is effectively a front locker. If there is steering input, the computer is going to disengage it because having your fwd-facing wheels locked in a turn is not a great idea. Mine unlocks in R consistently too, I would not worry about that.

The clunk sound: if you've ruled out other sources and it's for sure the diff, then it's from the clutch packs. I experienced this. I wound up replacing the diff and the locking actuator since the latter doesn't come with the diff. I think that was the culprit in fact because that out-going diff only had 18k miles on it but the actuator was original. I had the rear driveshaft changed too for the hell of it.

I don't know what the long term effects are of simply not fixing it. I couldn't live with the clunk since it's obviously non-normal. My LR3 is my baby and I'm gonna have it forever so I do stupid **** like that.