looking at your info and will replace the shaft first... I just wondering if the actuator is preventing from normal rear diff lock. But you know a lot more than I on this.

 

looking at your info and will replace the shaft first... I just wondering if the actuator is preventing from normal rear diff lock. But you know a lot more than I on this.

 

I had a GKN rear shaft arrive today. Bought from Parts Geek that sold two from GNK... I bought the one that said OEM in the description. was $439 and no idea if different from the other $100 cheaper or if I really have an OEM part.. There are no locking rings on the universal. So plan on replacing this week end and hope noise will go away. Will also remove, clean and reseal the rear diff locking actuator. The LR3 is very slow to engage rear lock. in every Terrain mode, high or low range, getting completely stuck, the rear usually will not lock. Only after multiple reverse then back up hill on the 10th or 12th attempt, the rear diff lock engages....and it makes a difference. After it engages once, it will engage and disengage as needed in all Terrain modes. It does always disengage in reverse.... even went uphill in reverse trying to make rear diff engage. There are no codes. I see some vehicles with locking actuators acting this way are failing and heard may cause damage to the pads in the diff. Should I replace? Rebuild? Leave it, thats how the LR3 is? I hate the idea of removing, cleaning, some repaint, then put back on a failing unit. I have seen on these threads a failing actuator can tear up a diff showing no codes and heard a failing actuator will throw a code. I can't believe this is the norm for an LR3

Anybody weigh in... Dakota Traveler, I am all ears.

 

My rear diff locks up without hesitation, and consistently.

 

Had the diff fluid changed when LR3 was bought a couple of months ago. This was a small shop that the LR dealer recommended since they would not check software older than 2011. Had all fluids changed and battery. They emailed receipt that simply said fluid changed... never told me what kind. I called and ask to send receipt with fluid type for all and claimed he used correct fluid for an e-diff.

Could open diff fluid cause this?

 

...but the LR (locking) rear diff fluid must be made with unicorn tears because it's spendy. There is a good chance that the Indy used the wrong stuff and from all I've heard it does matter.

 

Lets backup again. How do you know your locked is locked or not, using your display right? I have to say again that its commanded to do so based on parameters set by the program. Meaning a computer says to do it. It looks for wheel spin, steering angle, moon cycle and what you had for lunch. Its not the other way around. So if there is a physical problem with the locker the computer will not say hey... I am not going to lock as much as I would like to. Your program for when it would lock is the same as everyone else. And if the diff does not lock it can easily toss back a fault. Thats how the system works and monitors itself. Could there be a problem and no fault? Probably. But it also monitors wheel spin when locked and if there is too much of a difference between side its ALSO knows there is a problem and will fault. By the way, you are making me read WAYYYY more on tech info libraries than I wanted to! LOL

Fluids. For the rear e-diff locker you need the special carbon modified stuff as I mentioned before. BOT 720 can be found for $26/quart which is a STEAL if you know the source. Then there is the LR branded stuff (which is also BOT 720) that costs $4,500.22/quart, part number LR019727 is the latest. Then there is the General Motors equivalent, part number 92184900 which is about $30/quart also. Folks say the GM stuff is again Castrol stuff. Its used on very few GMs, like the Pontiac GTO. You can NOT use friction modifier, etc. If its in there a short while I dont think it will be an issue, but I can not say cause I really dont know. But longer term damage is guaranteed from what I have read. I will add that you can use the rear carbon mod stuff in the front or friction modifier in the front and it will not matter at all.

Quantities. The read e-diff uses about 2 quarts, front 1.5 quart (if I recall).

Transfer case uses manual transmission fluid. Royal Purple Synchromax is recommenced and what I used. You can NOT use differential fluid in the t-case unless you feel like replacing it soon. Quantity is about 2 quarts.

 

With the issues you seem to have, which is can not verify at all and since you dont have two trucks on the east same terrain we can not compare behavior. Your view of when it should lock will vary from my view, for example. But if you really think it should be locking and are operating it correctly, then maybe get your steering wheel angle sensor calibrated. If its off the vehicle may think you are in a turn when you are straight and the diff does act differently. For the diff to lock you sorta need to be going in a straight line. If an angle/speed threshold is met is will disengage. I do not have the values on hand for that though.

 

I get what your saying about comparative. However, when it is reluctant to rear lock, the front has already locked and driving straight. After multiple attempts on a small loose sand hill, driving straight, front locks every time, about 10th time of lost traction then reverse and back up hill, the rear will lock. After the initial rear lock, turning in loose sand both front and rear can usually remain locked.... sometimes the front will unlock then lock and same with rear, but it happens smoothly and quickly re-locks during a turn if traction loss. When working, both lock quickly over gravel with the front unlocking during a turn and rear may turn off briefly then on .... Once rear lock engages, front and rear function on and off smoothly on different terrains settings. It seems the initial rear lock is the issue at this point. Don't know if it matters, but the display correctly shows front wheel direction.BTW, initially, it was the 'Pop' sound that was a concern

I do understand somewhat, with your help, the e diff lock is computer controlled with input from steering, engine rpm, braking, and wheel speed to calculate best power to each wheel to minimize traction loss in each wheel. Different traction control settings are adjusting the value of inputs to best match situation. That said, I would expect the optional rear lock e diff on the LR3 would lock a bit sooner and more often.

With all that; why does it seem to work correctly after it finally engages the first time? It would seem the rear locker gets hung, but no faults. Then you think it is the computer or some calibration, but when it work, it works great... but not in reverse. I believe the should remain locked in reverse, but not positive.

The only way to be sure about the rear diff fluid, is to do it a second time.

This clip on youtube is an approximation of how I would get the rear diff to lock... just had to repeat multiple time before rear diff locked

 

....that you are in your own head at this point. It locks when it locks. No reason to over-think it or even try to anticipate whether it's working or not. You'd need live data with all the Terrain Response inputs to make such a determination. When it doesn't lock are you unable to make progress? You keep saying "front" in reference to the other diff, but I know you actually mean center.