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The differential with the flange is only on all model year 2020 defenders. All 2021 and up were changed to the large nut orientation, locking or open. It was a production change. The change is also inside the differential. 2020 with the flange has the ring gear bolted to the carrier. 2021+ with the large nut has the ring gear welded to the carrier. It was for weight savings i e fuel economy. The front differential from start of production has a welded ring gear and the large pinion nut. Hence, if you see a large nut on your pinion vs a flange, the ring gear is welded to the carrier. So, if you have a 2020 defender with an open differential, it is much easier to install an air locker. Later production involves machining the ring gear off the carrier and drilling and tapping it. That is one big benefit to the 2020 open diff. Also replacing the pinion seal on the 2020 is much easier than the later ones. Special tools are required. The large 12 point lock nut is super tight! And both use a crush sleeve for pinion bearing preload, so you have to put the nut back exactly where it is and count the turns. Otherwise,you are replacing pinion bearings.
Your insight & knowledge is always greatly appreciated!!
Thanks for sharing this info @sarek tremendously interesting.
I reckon there is no chance my local dealer would be able to do this without having to change bearings too. No chance.
on a side note I’m curious about the front diff. I have changed oil in rear diff and transfer case but do not see the front diff oil listed in the maintenance schedule. Is there an obvious reason for this I am too dumb to know? Can/should owners also change the front diff oil?
Manufacturer claims lifetime oil for the front. I still would drain and fill. Same with the transmission pan/filter and fluid.
Manufacturer claims lifetime oil for the front. I still would drain and fill. Same with the transmission pan/filter and fluid.
Great to know. I will look at the shop manual and see if I can get a how too. Hopefully as straight forward as the others. A drain and fill seems like a good preventative measure on these big ticket bits of hardware. My rear diff is definitely quieter (as in no noise little noises anymore) since the drain and fill.
@sarek would you recommend doing a transmission fluid flush around 70k miles? I know that’s what a lot of people do in the BMW world and on JLR products. ZF recommends to change it at 150k km or 93k miles.
I changed the fluid and filter on my old LR4 with the 6HP at 90k miles because I had some transmission issues. It was occasionally slipping. Had my shop change the fluid and filter, and it got significantly worse. Found out they didn’t use the ZF Lifeguard fluid and used a global synthetic that met ZF’s specs, even though I requested ZF fluid. Transmission blew up at 94k miles on my way home from the LR Experience Center at the Biltmore for an Owner’s Day. I had a good friend who owns a transmission shop who specializes in LR replace the transmission with a used one, and six weeks later I sold it because my Defender arrived.
I’d like to avoid this problem again. I don’t know how or why my transmission went bad, but I don’t want to take any chances. I know the 8HP is a much better gearbox than the 6HP, so that should help.
Update: not covered under the warranty. Dealer cleaned the rear differential, put leak detector in it (guessing some sort of UV leak detection fluid), drove it about 50 miles over 2 days, found no new leaking, washed the Defender, said "seepage is not covered by new car JLR warranty".
Also a bit of drama about them outright refusing to put my car on the rack / lift because "you have rock sliders" (Tuffant). And since they couldn't figure out how to put it on the rack, they could not check the level of fluid currently in the differential to ensure it was not low. It was at that point I asked for the car back because the conversation was so dumb I just decided I'd check the level myself at the house - bigger fishies to fry.
I'll give it a look with a UV light in 1000 miles to see if it is, in fact, leaking as I still don't think at 25K miles it should seep. Points for trying !?
Last edited by nashvegas; Dec 27, 2024 at 11:09 PM.
Update: not covered under the warranty. Dealer cleaned the rear differential, put leak detector in it (guessing some sort of UV leak detection fluid), drove it about 50 miles over 2 days, found no new leaking, washed the Defender, said "seepage is not covered by new car JLR warranty".
Also a bit of drama about them outright refusing to put my car on the rack / lift because "you have rock sliders" (Tuffant). And since they couldn't figure out how to put it on the rack, they could not check the level of fluid currently in the differential to ensure it was not low. It was at that point I asked for the car back because the conversation was so dumb I just decided I'd check the level myself at the house - bigger fishies to fry.
I'll give it a look with a UV light in 1000 miles to see if it is, in fact, leaking as I still don't think at 25K miles it should seep. Points for trying !?
Land Rovers Finest.
"Your diff seal is leaking. This is fine. Totally normal for things to leak on a 20,000 mile vehicle
We can't lift your vehicle as it has sliders that are two enormous jacking points and we're all out of ideas
Don't even need a lift to access rear diff but that's beside the point."
@sarek would you recommend doing a transmission fluid flush around 70k miles? I know that’s what a lot of people do in the BMW world and on JLR products. ZF recommends to change it at 150k km or 93k miles.
I changed the fluid and filter on my old LR4 with the 6HP at 90k miles because I had some transmission issues. It was occasionally slipping. Had my shop change the fluid and filter, and it got significantly worse. Found out they didn’t use the ZF Lifeguard fluid and used a global synthetic that met ZF’s specs, even though I requested ZF fluid. Transmission blew up at 94k miles on my way home from the LR Experience Center at the Biltmore for an Owner’s Day. I had a good friend who owns a transmission shop who specializes in LR replace the transmission with a used one, and six weeks later I sold it because my Defender arrived.
I’d like to avoid this problem again. I don’t know how or why my transmission went bad, but I don’t want to take any chances. I know the 8HP is a much better gearbox than the 6HP, so that should help.
I would not flush it, but drain and fill with a new pan/gasket only with oem ZF /JLR parts. Also, if you are experiencing a symptom, typically filter fluid change may not be the best path forward. We primarily offer this as preventative maintenance, not to fix a symptom unless the pan is leaking and the fluid level is low. Also a proper repair with proper materials needs to be performed. A specific fill procedure needs to be followed. It seems that may have not happened in your case. 70k is a good interval. I did mine at 50k, but I push my vehicle hard with towing and off road use. As zf states, heavy use shortens the interval.
Update: not covered under the warranty. Dealer cleaned the rear differential, put leak detector in it (guessing some sort of UV leak detection fluid), drove it about 50 miles over 2 days, found no new leaking, washed the Defender, said "seepage is not covered by new car JLR warranty".
Also a bit of drama about them outright refusing to put my car on the rack / lift because "you have rock sliders" (Tuffant). And since they couldn't figure out how to put it on the rack, they could not check the level of fluid currently in the differential to ensure it was not low. It was at that point I asked for the car back because the conversation was so dumb I just decided I'd check the level myself at the house - bigger fishies to fry.
I'll give it a look with a UV light in 1000 miles to see if it is, in fact, leaking as I still don't think at 25K miles it should seep. Points for trying !?
Classic!
So they put "leak detector" in the locking rear differential? Why do you need that to see a leak....it would just leak and you would see oil. That is just ridiculous. The big issue is that they just contaminated the diff oil with a non approved fluid. That rear locker is sensitive as it is with the special fluid that is required. Did they use JLR dye? If that is the case, i have never heard of that. Also, they should show you in your warranty contract where it says seepage is not covered. I agree,it is not a major leak, but it is wet there. Telling you they would like to clean and reinspect after some mileage and check the level seems reasonable. But leak detection fluid....really? I would love to see proper documentation on this diagnostic path. Again, i have seen crazier things from a manufacturer, so i wont say it is impossible.
I had the exact same thought—'What was put in there?'—and wondered if it could be a contamination issue. Interesting to hear you had a similar reaction / reassuring to know I’m not imagining things.
This weekend, I’m now planning to hit a nearby trail in the snow. Full send! I’ll aim to create conditions that could exacerbate the seep or leak, lock center/rear, wheelspin. Basically, I’ll rough-house it and see what happens. The bloodhound needs to get out of the house anyways..
Here is what it looks like now after the cleaning. So it will be very obvious if it leaks even a drop.
To follow up on this 13 months later. I changed the rear locking diff fluid today early and glad I did. A couple of findings;
Old fluid was thick dark black. New fluid is amber. I only have like 30K something miles. Moderately heavy offroad use case though.
Magnetic drain plug had a small layer of sludge on it (felt like a bit of dark play dough) -- but I could not see any metallic glints or sheen to the oil or that sludge. Moving the sludge between my fingers, no metal bits I could figure out. So clearly there’s some sludge (clutch gak maybe?) at the bottom of the differential ... reason enough maybe to change fluid.
I used new drain and fill plugs. Neither uses a copper washer but for some reason I bought them when ordering parts.
It is supposed to take ~1.22-1.24 L of fresh fluid with a wet refill. I put about 1.4 L in before it started coming out the fill hole.
Most annoyingly when I went underneath to start the job, I realized the differential is leaking at this bloody pinion seal they told me wasn’t leaking pre-warranty expiration. Oh well. So basically if you find yours seeping like mine was, it’s probably going to get worse.
That’s the driveshaft going towards front of car on the left there. leaking out the seal around the driveshaft, down, and then moving back with wind I guess... This is before I touched anything.
