For anyone who is curious - I sent 4 oils to Blackstone after my summer overhaul project on my '15 XFR-s with 45k miles on it.

Engine Oil - OEM Castrol 0W-20 (4k/year)
S/C Oil - OEM Eaton/Jaguar Oil (45k/7years)
Trans Oil - ZF LG8 (45k/7years)
DIff Oil - E-Diff, OEM Castrol (45k/7years) **This is the only one that had a worrisome report**

The car had one previous owner with dealer service records, so as far as I could tell, it had only received "regular" oil changes per the service guide. If anything, they were done on the time basis, not mileage, as this car was a bit under driven. For anyone who has not used this service, its really cool and takes about 1-2 weeks depending on their workflow. Its $30 per sample. After a lot of service, a dyno, and some seat time I wanted to see if there were any problems with the car before I start modifying it. For what its worth... the e-diff functions fine, I will likely follow their instruction and change the fluid again in 5k mi or so.

Reports are attached!

 

Hope your E-diff is OK.
When I changed the fluid in mine it was very dirty and black looking. Thick and kind of chunky too. What I read was these have CF clutches and they shed carbon which of course is jet black. So I did not worry about it and new fluid is always good. That was about 7K-10K miles ago and so far it seems fine. I do race a bit so it's seen very high speeds too.

Sure glad at least for the rear end Jaguar made it very simple to service. Has a drain and fill plug but of course Jaguar had to make both plugs DIFFERENT!
Why Jaguar?? Ones square and ones hex.
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I wish it was simple for the dealership, had a 2014 3.0 that had a rear diff seal recalled so they fixed it and forgot to add the fluid. Fried the rear end and then tried to say it was our fault. Ended up replacing under the extended warranty and I was far from impressed.

 

Just wanted to share my experience for anyone interested to know about E-Diffs in the V8 Supercharged models

I did my first Diff fluid change at 40K miles. It was terrible looking and I had symptoms or grinding while turning. After the first change it was good as new, well for only 3K miles (@43K miles) then it started the damn grinding feeling/noise again while turning and applying throttle at low speeds. At this point I was convinced I needed a new diff.

Looking online for new units + labor I was about to fork out $3000 to change it. So I had to do "The Last Hurrah" approach and change the fluid again but this time decided to add AMSOIL friction modifier/ Clutch treatment fluid with the diff fluid (Which was also Amsoil Gear oil 75-90) and this was done again @ 43K miles and about 6 months ago

Fast forward to today 13/12/2021 and 10K miles later the diff still functions flawlessly.

Hope this helps anyone/everyone searching for a solution

 

Thank you so much @DeviLSh for the oil analysis, I have a diff flush scheduled this week.

And thanks for the additive recommendation @croco, I have the same grinding and grabbing diff symptoms at 43k. How many ounces of the additive did you add? I see recommendations for around 2-4 ounces.

 

not sure it was the size of a small tooth paste that says enough for 2-4 quarts. I'd say 2-4 ounces should do the trick

 

I bought the LR e-diff oil which supposedly already comes with additives, so I opted not to mix anything else. No more grabbing and rear end shimmy and the old oil was well beyond healthy. Highly recommend everyone with an e-diff to get this done at a 2yr/20k mile frequency at the most. The weird part is, my 2012 XFR had 80k hard driven miles (mountain runs, 1/4 miles, drifting, donuts/burnouts) on the original oil and I never had any diff issues.

 

Interesting about the additives as I have never heard any recommendation except to use the proper rated rear diff oil.
croco your signature shows a 2004 model? These did not come with the E-diff so a completely different animal.
Did you put the additive in a E-diff unit? Maybe in a different car?
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Nope this signature was before I bought my 2014 XFR. The mentioned above was done on my XFR with E-Diff unit.