There seems to be little discussion on the HD versions and specifically the rear locker on most forums. Just last week I got all the Christmas lights on my dash and lowered suspension. Turned out it was my rear locker having issues and after a few hits with a hammer on the motor above the diff, everything came back to life. Now I’ve got no lights on the dash, suspension went back up, and everything drives perfectly.

So I’m pretty sure I need a new rear diff motor. Seems like it’s getting stuck after being being engaged while off roading for very long. However, I’m a willing guinea pig if any of you have ideas on how to service or repair the motor before just buying a new one. I read somewhere about a guy that drilled a hole in his and blasted it with some lube and it came back from the dead.

Let’s hear it - how would you suggest I fix this? Where should I start?

 

Pull it apart and see where the issue is, it may be easier to just replace the whole unit.

 

Yeah it would be nice to know the faults and all that. I've never had that happen to a failed actuator. More typically there is a soft fault related to clutches and a "clank" noise that is noticeable under load. Can we assume that you've ruled out the usual suspects (battery, brake switch, steering angle sensor, etc)? Could the issue be the Diff Control Module rather than the actuator? I think a lonnnnng time ago (like 2005) I had an issue like that and the dealership claimed that it was the Control Module but that was back in the day when nobody really knew how to work on the LR3 and they would just change parts wholesale and everything was under warranty.

 

So this wasn't the first time I've had to smack it with a hammer but usually I get a "transmission fault - traction reduced" message on the dash and if I continue to push you can tell that the rear diff won't lock anymore (and the screen confirms as much). As you probably know there's a small sound that you hear when you turn the vehicle on, which is a good sound I believe. When I get the above-mentioned fault I don't hear that sound and I'll get the same message on startup every time unless I recalibrate with the GAP tool or smack it with a hammer. What made this last episode strange was it set off a million lights, dropped suspension, and said "transmission fault - slow down" or something like that.

To answer some of your questions, yes I've swapped the brake switch, new-ish battery, and I've calibrated the SAS and inspected to verify it's still attached and tracking properly. The readout on the GAP tool is very precise when moving the wheel; no lag or anything. I supposed it could be the control module but the fact that hitting it with a hammer fixes it every time, without fail, makes me think it's mechanical and it's getting stuck. Hence my thoughts of drilling and lubricating to see if that helps. But would be open to other "theses" on the issue!

 

Yeah that is interesting. Maybe it's a more advanced stage of what I have experienced. Here is all that I've gone through, diff-wise:

1. In 2005, the situation where the dealership changed the control module. It had caused the million lights scenario as you describe.
2. A handful of years ago I remember getting a "traction reduced" message. Of course it was when I was off road and about to climb a serious hill. I never really tracked it down and blew it off as a phantom.
3. Around the same time, I had an actuator issue on the rear diff and the clutch packs had went. I started getting a "clank" and changed the diff and the actuator.

....I guess that now explains the traction reduced message I'd gotten. Thanks!

 

There is nothing in the coding for the rear diff that will cause a hard fault, you have multiple issues.

As for the actuator, its not the worst thing to remove and service/replace. Just make sure you clean under there very well before proceeding. Story time: I replaced mine a year or so ago. I had a clank, thought it was the upper arms at one point. Guess it was not because I started to get codes for actuator being stuck/position not learnt. Replaced it with an aftermarket. If I recall, the stuck code was gone but I was plagued with position not learnt for a while until one day it just never came back and it was fine every since this past weekend. I went off-road and did some interesting stuff. Now I am getting a stuck code only, again... I already had a replacement actuator for the company that sold the last since it seemed defective. If this replacement causes faults, I will get an OEM unit from the UK for $300 but I am also strongly suspecting the module itself and may try a used one first. But I never had any hard faults, just the passive "traction reduced" message and again now since this weekend. I suggest you get us a full list of codes.

I have a thread on my replacement process:
https://landroverforums.com/forum/lr...ection-101515/

edit: Oh.... I also plan to very much inspect all the wiring. Given the behavior I had with the current replacement after install, I can not rule out bad wiring. Already had bad wiring take out my fuel pump power.

 

Just going to add this story to the mix, it happened today. So I looked at how everything talks and still could not see how a rear diff fault could cause issues so I tried something I have not done before. I think it lead to some sorta rear diff module corruption. All I did was perform a self-test of the rear diff - and it passed, oddly enough. For the rear diff and a GAP tool, I think that is the only test one can do. And that did it, DSC light flashing, ABS light one and once I started to move, it lowered to access height (def not bump stops).

So phase one, clear codes. Nothing helped.
Did a self-test again, cleared codes, nothing helped.
I pulled up codes and had no new rear diff faults besides being stuck, but I DID have a vehicle dynamics fault saying invalid data from the diff module, algorithm based failure. U1A4A-68.
So I said screw it and removed the read locking diff from the CCF.
Well crap, still faults even WITH the rear diff - even though now removed. In fact now the vehicle dynamics is thrown more codes.
Drove a bit.
Got to a store, restarted to get air ride back to normal height at least.
Went shopping.
Came out preparing to pull EAS fuse to maintain height yet not a single error came up. None.

I think I simply did not let the truck "shutdown" long enough between some events when it came to clearing codes, etc. I did try waiting two minutes, maybe not long enough really. But this is my experience so maybe there is a small bit of data that could help. For now I am running with no rear diff fitted in the CCF file and all seems well. For me though, I am leaning even more towards wiring issue or even the diff module itself at this point. During the self-test you can hear it operate the range of actuation.

 

I wanted to disable the rear locking diff on my 06 as it constantly faulted. I to used to hear an odd little noise at shutdown from that area and when that sound stopped the fault started. I was going to replace the motor, but the Mrs had enough with the LR3 and wanted it gone. If I ever venture back into an LR3 or a RRS I honestly don't want that option as it seems to be just 1 more thing to fail.

Off the subject a bit I'm seeing more 05/06 LR3's out on the trails lately and I am honestly shocked at the amount of rust these things are starting to have. From skid plates for the fuel tank with massive holes, rear brake splash shields completely rotten thru, and then the rear bumper area where you access the hitch or tow point. And these are on TX trucks...... I thought LR did a poor job with the RRC/D1 and rust proofing, but I am starting to wonder about the LR3/RRS after seeing at least 5 with pretty serious rust in my books and not from a state known for salting the roads during the winter.

 

Well, you won't have any problem finding a non-HD variant out there, so you're in luck!

I would say it's "One more thing to maintain" rather than 1 more thing to fail. Same point, I guess, but the locker is not some trivial thing like a heated seat. Anyway, the rust thing...I have to wonder how much of that comes down to maintenance as well....and have those trucks always lived in TX? Both of mine ('05 with locker, '06 without) are rust free up here in the Pacific NW. On the '05 I spend one day every year sanding and painting the areas where there is rust (mostly because I've scratched off the paint on rocks and such, so surface rust forms), then I go over all of it with an anti-corrosion spray.

Frame looks like this when I'm done:

 

2 of the LR3's I know for sure are pure TX trucks. They do off road them often so I'm sure water easily gets between the fuel tank and the skid plate and just sits there (if the drain holes are full of gunk). No reason why the rear area by the recovery hook looks so bad either to be honest. On my 06 the only really rusty area was where those 2 counter balance weights were. It wasn't Titanic bad by any means, but it was noticeable rust for sure.

Yeah when I bought the 06 LR3 I specifically hunted down the HD Package because when the wife wanted something else I was going to mod it and off road it. That LR3 started off fine then electrical glitches started to appear that even my best friends LR shop couldn't fully track down. Once we had those pretty well sorted out the Transmission Fault started and of coarse I immediately figured out it was the locking diff vs actual transmission issue. Maybe it failed because I didn't off road it lol, but I had it re-calibrated 2 times and the last time I didn't even make it home before it faulted out again after I filled up for fuel. I was told two options replace motor & if it faulted again = replace the entire rear diff. That's when my wife said adios to it lol. I was going to just keep it, but we sold it and used the $$$$ as a down payment for the vehicle she wanted.